diff --git a/.github/workflows/cross-library.yml b/.github/workflows/cross-library.yml
new file mode 100644
index 0000000000..8f4e063129
--- /dev/null
+++ b/.github/workflows/cross-library.yml
@@ -0,0 +1,279 @@
+name: cross-library (reusable)
+
+# Reusable engine for compile-testing a downstream wolfSSL product against the
+# wolfSSL in this checkout. It builds wolfSSL once from this checkout (the PR
+# merge commit) with the flags a product needs, then compiles the product
+# against that install at both the product's default-branch HEAD and its highest
+# release tag (compile-only, no `make check`).
+#
+# The wolfSSL build runs once and is shared: the build-wolfssl job installs
+# wolfSSL and uploads it as an artifact, and the compile matrix (head, latest)
+# downloads that artifact instead of rebuilding. This halves the wolfSSL builds
+# per product from two to one.
+
+on:
+  workflow_call:
+    inputs:
+      product:
+        description: 'Short product label (used for the job name)'
+        required: true
+        type: string
+      repo:
+        description: 'Product source: "owner/repo" shorthand or a full git URL'
+        required: true
+        type: string
+      wolfssl_configure:
+        description: 'Configure flags for the local wolfSSL build'
+        required: true
+        type: string
+      product_configure:
+        description: "The product's own ./configure flags"
+        required: false
+        default: ''
+        type: string
+      script:
+        description: 'Build script name under .github/workflows/cross-library/scripts/'
+        required: true
+        type: string
+      apt_packages:
+        description: 'Extra apt packages needed to build the product'
+        required: false
+        default: ''
+        type: string
+      container:
+        description: 'Container image to build in (e.g. ubuntu:24.04, debian:13)'
+        required: false
+        default: 'ubuntu:24.04'
+        type: string
+
+jobs:
+  # Build wolfSSL once and publish the install dir. Both compile legs (head,
+  # latest) consume it, so this runs a single time per product instead of once
+  # per leg.
+  build-wolfssl:
+    name: Build wolfSSL (${{ inputs.product }})
+    if: ${{ (github.repository_owner == 'wolfssl') && (github.event_name != 'pull_request' || github.event.pull_request.draft == false) }}
+    runs-on: ubuntu-24.04
+    container:
+      image: ${{ inputs.container }}
+    timeout-minutes: 20
+    steps:
+      # Minimal-image containers ship without git/toolchain; install them
+      # before checkout. Product-specific extras come from apt_packages.
+      - name: Install build tools
+        run: |
+          set -eux
+          export DEBIAN_FRONTEND=noninteractive
+          apt-get update
+          apt-get install -y --no-install-recommends \
+            build-essential autoconf automake libtool pkg-config \
+            git ca-certificates ${{ inputs.apt_packages }}
+
+      # Building only needs the commit under test, not history. The break check
+      # that needs history runs in the compile job, not here.
+      - name: Checkout wolfSSL
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 1
+          fetch-tags: false
+
+      # Container job: the bind-mounted workspace is owned by a different uid,
+      # so mark it safe or git refuses to operate on it ("dubious ownership").
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      # Build wolfSSL and install to a local dir. The configure flags go through
+      # an env var (not inline ${{ }}) so a quoted CFLAGS/C_EXTRA_FLAGS group
+      # survives GitHub's expansion intact; the string is trusted caller input
+      # that build-wolfssl.sh eval's.
+      - name: Build and install wolfSSL
+        env:
+          WOLFSSL_CONFIGURE: ${{ inputs.wolfssl_configure }}
+        run: |
+          .github/workflows/cross-library/scripts/build-wolfssl.sh \
+            "$GITHUB_WORKSPACE" \
+            "$GITHUB_WORKSPACE/wolfssl-install" \
+            "$WOLFSSL_CONFIGURE"
+
+      # Pack as a tar so libtool symlinks, exec bits, and the absolute-path
+      # .la/.pc files survive the artifact round-trip. The compile job unpacks to
+      # the same $GITHUB_WORKSPACE path, so those baked-in paths stay valid.
+      - name: Pack the wolfSSL install
+        run: tar -C "$GITHUB_WORKSPACE" -czf wolfssl-install.tar.gz wolfssl-install
+
+      - name: Upload the wolfSSL install
+        uses: actions/upload-artifact@v4
+        with:
+          name: wolfssl-install-${{ inputs.product }}
+          path: wolfssl-install.tar.gz
+          retention-days: 1
+
+  # Compile the product against the shared wolfSSL, once per ref_mode:
+  #   head    -> HEAD of the product's default branch (master/main, auto-detected)
+  #   latest  -> the product's highest version tag (polled at run time)
+  compile:
+    name: Compile ${{ inputs.product }} (${{ matrix.ref_mode }})
+    needs: build-wolfssl
+    runs-on: ubuntu-24.04
+    container:
+      image: ${{ inputs.container }}
+    timeout-minutes: 25
+    strategy:
+      fail-fast: false
+      matrix:
+        ref_mode: [ head, latest ]
+    steps:
+      # Minimal-image containers ship without git/toolchain; install them
+      # before checkout. Product-specific extras come from apt_packages.
+      - name: Install build tools
+        run: |
+          set -eux
+          export DEBIAN_FRONTEND=noninteractive
+          apt-get update
+          apt-get install -y --no-install-recommends \
+            build-essential autoconf automake libtool pkg-config \
+            git ca-certificates ${{ inputs.apt_packages }}
+
+      # This job does not build wolfSSL, but the latest leg still checks out
+      # wolfSSL history because check-break.sh scans commit messages here. The
+      # head leg never waives a break, so a depth-1 checkout is enough for it.
+      - name: Checkout wolfSSL
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 1
+          fetch-tags: false
+
+      # This is a container job: the workspace is a host bind-mount owned by a
+      # different uid than the (root) container user, so git refuses to operate
+      # on it ("detected dubious ownership") unless it is marked safe. actions/
+      # checkout marks it safe only under its own *temporary* HOME, which our
+      # run: steps (HOME=/github/home) do not inherit, so check-break.sh's
+      # `git tag`/`git log` would fail and, with stderr hidden, look like "no
+      # break declared". Mark it safe under this HOME for all following steps.
+      - name: Mark workspace safe for git
+        run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
+
+      # The `latest` leg is the only one that reads wolfSSL history: it needs the
+      # commit messages check-break.sh scans (the last two release cycles) plus
+      # the two newest release tags, and no file contents, so --filter=tree:0
+      # fetches commits+tags only and turns a 912 MiB full clone into ~1 MiB on
+      # top of the source. The exclude boundary is the THIRD-newest release, not
+      # the scan base, because --shallow-exclude severs the ref it names and
+      # severing the scan base would drop it from `git tag --merged HEAD` and
+      # silently halve the window. Tags come in by explicit refspec (never
+      # --tags, which re-pulls every tag's history), and note a server without
+      # uploadpack.allowFilter silently ignores the filter and clones in full.
+      - name: Deepen wolfSSL history for the break check
+        if: ${{ matrix.ref_mode == 'latest' }}
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          # Release-tag selection MUST agree with check-break.sh's
+          # `--list 'v*-stable' --sort=-v:refname`. `sort -Vr` matches git's
+          # -v:refname on this tag set (verified incl. double-digit minors,
+          # e.g. v5.9.10 > v5.9.2). The assertion below catches any drift.
+          mapfile -t T < <(git ls-remote --tags --refs origin 'v*-stable' \
+              | sed 's#.*refs/tags/##' | sort -Vr)
+          echo "Newest release tags: ${T[*]:0:3}"
+
+          if [ "${#T[@]}" -lt 3 ]; then
+            echo "Fewer than three release tags; falling back to full history."
+            git fetch --unshallow --filter=tree:0 --tags origin
+          else
+            # Fetch by ref (not raw SHA) so this does not depend on the server
+            # allowing reachable-SHA1-in-want.
+            git fetch --no-tags --filter=tree:0 --shallow-exclude="${T[2]}" origin \
+                "$GITHUB_REF" \
+                "refs/tags/${T[0]}:refs/tags/${T[0]}" \
+                "refs/tags/${T[1]}:refs/tags/${T[1]}"
+          fi
+
+          # Fail LOUD if this step and check-break.sh disagree on the scan base.
+          # check-break.sh:61 falls back to the NEWEST tag when the second line
+          # is missing, which would quietly halve the window rather than error.
+          rel="$(git tag --merged HEAD --sort=-v:refname --list 'v*-stable')"
+          base="$(printf '%s\n' "$rel" | sed -n '2p')"
+          echo "Deepened to $(git rev-list --count HEAD) commits; scan base='${base}'"
+          if [ -z "$base" ]; then
+            echo "::error::Deepen produced no usable scan base; check-break.sh would scan the wrong window."
+            printf 'Release tags merged into HEAD: %s\n' "${rel:-<none>}"
+            exit 1
+          fi
+
+      - name: Download the wolfSSL install
+        uses: actions/download-artifact@v4
+        with:
+          name: wolfssl-install-${{ inputs.product }}
+
+      # Unpack to the same path wolfSSL was built at, keeping the .la/.pc
+      # absolute paths valid.
+      - name: Unpack the wolfSSL install
+        run: tar -C "$GITHUB_WORKSPACE" -xzf wolfssl-install.tar.gz
+
+      # Resolve the concrete ref to compile: the highest tag (latest) or the
+      # default branch (head). Used both for the build and the break check.
+      - name: Resolve product ref
+        id: ref
+        env:
+          REPO: ${{ inputs.repo }}
+        run: |
+          ref="$(.github/workflows/cross-library/scripts/resolve-ref.sh "$REPO" "${{ matrix.ref_mode }}")"
+          echo "Resolved ${{ matrix.ref_mode }} ref for $REPO: $ref"
+          echo "ref=$ref" >> "$GITHUB_OUTPUT"
+
+      # Compile-only (never `make check`). A compile failure is allowed ONLY if
+      # a wolfSSL commit since the last release tag declared it with a
+      # `breaks-<product>=<ref>` token (see check-break.sh); otherwise the job
+      # fails, forcing intentional breaks to be recorded in a commit.
+      # PRODUCT_CONFIGURE is intentionally unquoted so multiple flags split.
+      - name: Compile ${{ inputs.product }} against wolfSSL
+        env:
+          REPO: ${{ inputs.repo }}
+          PRODUCT_CONFIGURE: ${{ inputs.product_configure }}
+          PRODUCT: ${{ inputs.product }}
+          REF: ${{ steps.ref.outputs.ref }}
+          MODE: ${{ matrix.ref_mode }}
+        run: |
+          S=.github/workflows/cross-library/scripts
+          set +e
+          # shellcheck disable=SC2086  # $PRODUCT_CONFIGURE must word-split into flags
+          "$S/${{ inputs.script }}" -t "$REF" \
+            "$GITHUB_WORKSPACE/wolfssl-install" "$REPO" $PRODUCT_CONFIGURE
+          rc=$?
+          set -e
+
+          # The breaks-<product>= mechanism applies ONLY to the latest release
+          # tag. A head/master break is never waivable, never consults the
+          # ledger, and must be fixed.
+          if [ "$rc" -eq 0 ]; then
+            if [ "$MODE" = "latest" ] && "$S/check-break.sh" "$PRODUCT" "$REF" >/tmp/brk 2>/dev/null; then
+              echo "::warning::$PRODUCT ($REF) compiled OK but a break is still declared, remove the stale breaks-$PRODUCT=$REF token:"
+              cat /tmp/brk
+            fi
+            exit 0
+          fi
+
+          echo "===== $PRODUCT ($REF) failed to compile against this wolfSSL ====="
+
+          if [ "$MODE" = "latest" ]; then
+            # Released, immutable tag: allowed only if the exact tag is declared.
+            if "$S/check-break.sh" "$PRODUCT" "$REF"; then
+              echo "::warning::$PRODUCT $REF failed to compile, but this break is DECLARED (see above). Treating as a known/tracked break."
+              exit 0
+            fi
+            echo "::error::$PRODUCT $REF (latest release) no longer compiles against this wolfSSL and no break is declared."
+            echo "That tag is a released version and cannot be changed. If wolfSSL is intentionally dropping"
+            echo "compatibility with it, record the break so CI tracks it and this job passes. Add this exact"
+            echo "token to a commit message in this PR (the release must be named explicitly):"
+            echo "    breaks-$PRODUCT=$REF"
+            echo "Otherwise, rework the change so $PRODUCT $REF still builds."
+          else
+            # Product master/HEAD: NEVER waivable, no breaks- declaration exists.
+            echo "::error::$PRODUCT $REF (default branch) no longer compiles against this wolfSSL."
+            echo "A master/HEAD break cannot be waived; there is no breaks- declaration for it."
+            echo "$PRODUCT $REF must stay compatible with wolfSSL master. Fix it by either:"
+            echo "  * reworking this PR so $PRODUCT $REF builds against wolfSSL master again, or"
+            echo "  * putting up a matching fix on $PRODUCT's $REF branch, then re-running this job."
+          fi
+          exit 1
diff --git a/.github/workflows/cross-library/README.md b/.github/workflows/cross-library/README.md
new file mode 100644
index 0000000000..4dc553683f
--- /dev/null
+++ b/.github/workflows/cross-library/README.md
@@ -0,0 +1,124 @@
+# Cross-library compile testing
+
+Compile tests the wolfSSL product family (wolfSSH, wolfCLU, wolfTPM, wolfMQTT,
+wolfPKCS11, wolfProvider) against **this** wolfSSL, so a wolfSSL change that
+would stop a downstream product from *compiling* is caught in CI.
+
+**Compile only. There is no runtime testing here** (the product scripts run
+`make`, never `make check`). Each product is built twice: at the HEAD of its
+default branch and at its latest tagged release.
+
+> Note: the workflow `.yml` files (the reusable engine `cross-library.yml` and
+> the per-product `cross-<product>.yml` callers) live in `.github/workflows/`
+> itself, because GitHub only discovers workflows directly in that directory,
+> not in subfolders. Everything else (these scripts) lives here.
+
+## Layout
+
+```
+.github/workflows/
+  cross-library.yml          # reusable engine (on: workflow_call)
+  cross-<product>.yml         # one thin caller per product (matrix: head, latest)
+  cross-library/
+    README.md                 # this file
+    scripts/                  # all the machinery
+```
+
+## How a run works (per product, per ref)
+
+The engine (`cross-library.yml`) runs one job in a clean container
+(`ubuntu:24.04` by default; a caller may pass `debian:13`):
+
+1. **Install build tools** with `apt-get` (`+ apt_packages` from the caller).
+2. **Checkout wolfSSL** (full history + tags, for the break check below).
+3. **`build-wolfssl.sh`** builds this checkout's wolfSSL with the product's
+   required `wolfssl_configure` flags and installs it to a local dir.
+4. **`resolve-ref.sh`** resolves the ref to build: the highest version tag
+   (`ref_mode: latest`) or the default branch (`ref_mode: head`).
+5. **`<product>.sh`** clones the product at that ref and compiles it against the
+   installed wolfSSL (`--with-wolfssl=<install dir>`).
+6. If the compile fails, **`check-break.sh`** decides whether it was a
+   *declared* break (allowed, tracked) or an *undeclared* one (job fails). See
+   below.
+
+## Scripts
+
+| Script | Role |
+|---|---|
+| `build-wolfssl.sh <src> <install> <configure>` | Build and install wolfSSL from `<src>`. Configure flags are one `eval`-ed string so a quoted `CFLAGS=`/`C_EXTRA_FLAGS=` group survives. |
+| `common.sh` | Shared helpers: `resolve_repo_url`, `default_branch` (master/main auto-detect), `latest_tag`, and `cross_build_autotools` (clone, configure `--with-wolfssl` plus `-I`/`-L`/rpath/`PKG_CONFIG_PATH`, then `make`). |
+| `resolve-ref.sh <repo> <mode>` | Echo the ref for `head` (default branch) or `latest` (highest tag). |
+| `latest-tag.sh <repo>` | Poll the highest version tag (`git ls-remote --sort=-v:refname`, robust to mixed tag styles). |
+| `check-break.sh <product> <ref>` | Break declaration check (see below). |
+| `<product>.sh [-t <ref>] <install> <repo> [product_configure...]` | Per-product build. Most just call `cross_build_autotools`; `wolfprovider.sh` also passes `--with-openssl`. |
+
+## Break declarations
+
+Testing a product's last *release* against wolfSSL HEAD can legitimately fail
+when wolfSSL intentionally changes an API. This applies **only to the `latest`
+(release-tag) leg**. To keep such a break honest and auditable, it must be
+**declared in a wolfSSL commit message** with a token naming the **exact release
+tag**:
+
+```
+breaks-<product>=<tag>      e.g.  breaks-wolfssh=v1.5.0-stable
+```
+
+There is **no `latest`/`head`/`*` shorthand**. The broken release must be named
+explicitly, so every newly-broken release needs its own fresh, reviewable
+declaration (an old token simply stops matching once the tag moves on).
+
+**A `head` (master) break is never declarable.** If a product's default branch
+stops compiling against wolfSSL master, there is no token to wave it through.
+The PR must be reworked, or a fix put up on the product's master. A token whose
+value is `head`, `master`, `main`, or `*` is ignored outright.
+
+`check-break.sh` scans wolfSSL commits for a matching token (case-insensitive)
+over a window of the **last two wolfSSL release cycles**, from the
+*second-newest* `v*-stable` release tag to HEAD. Two cycles (not one) so that
+when wolfSSL cuts a new release, a break declared in the prior cycle keeps being
+honored for one more cycle, giving the downstream product time to ship a fixed
+release before PRs go red again for the same known issue. (Release tags are
+picked by version order, not commit ancestry, so wolfSSL's many non-release tags
+like `*-CHKIN` are ignored.) Then the engine:
+
+| Compile | Declared? | Result |
+|---|---|---|
+| passes | no | green |
+| passes | yes | green, plus a warning to remove the now-stale token |
+| fails | yes | green, plus a warning "known/tracked break" (shows the commit) |
+| fails | no | red. Fix it, or add a `breaks-<product>=<tag>` token |
+
+Because the token names the exact tag, it automatically stops matching once the
+product releases a newer tag, forcing a fresh, explicit declaration if the new
+release is still broken.
+
+The failure message depends on which leg broke:
+
+- **`latest` (a released tag)**: the tag is immutable, so the job explains the
+  `breaks-<product>=<tag>` mechanism and asks you to either declare the break
+  (to track it and go green) or rework the change so the release still builds.
+- **`head` (the product's default branch)**: this is expected to track wolfSSL
+  and is **never waivable**. The job fails and asks you to **rework the PR or put
+  up a fix on the product's master branch**. There is no break declaration for a
+  head failure.
+
+## Adding a product
+
+1. Copy an existing `cross-<product>.yml` caller and set `product`, `repo`,
+   `wolfssl_configure` (the wolfSSL flags that product documents), optional
+   `product_configure`, `script`, and optional `apt_packages`.
+2. Add a `scripts/<product>.sh`. If it is a standard autotools project, it is
+   just:
+   ```sh
+   #!/usr/bin/env bash
+   DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+   . "$DIR/common.sh"
+   cross_build_autotools "$@"
+   ```
+   Non-autotools products (see `wolfprovider.sh`) can `_prepare "$@"` and then
+   run their own build steps.
+
+Get each product's required `wolfssl_configure` from that product's own
+README or CI, not by guessing. The flags matter (e.g. wolfPKCS11 and
+wolfProvider need specific `C_EXTRA_FLAGS`/`CFLAGS` defines).
diff --git a/.github/workflows/cross-library/scripts/build-wolfssl.sh b/.github/workflows/cross-library/scripts/build-wolfssl.sh
new file mode 100755
index 0000000000..21c0828072
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/build-wolfssl.sh
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+#
+# Build the wolfSSL sources in <src_dir> with the given configure flags and
+# install to <install_dir>. In CI <src_dir> is this checkout (the PR merge
+# commit). The resulting <install_dir> is handed to a product build script so
+# it can locate wolfSSL via --with-wolfssl=<install_dir>.
+#
+# Compile + install only; wolfSSL's own tests are not run here.
+#
+# The configure flags are one string (not separate args) and are `eval`-ed so a
+# quoted CFLAGS/C_EXTRA_FLAGS group survives intact, e.g.
+#   --enable-all CFLAGS="-DWC_RSA_DIRECT -DHAVE_AES_ECB"
+# The string comes from our own caller workflows (trusted input).
+#
+# Usage: build-wolfssl.sh <src_dir> <install_dir> <configure_string>
+
+set -euxo pipefail
+
+src="$1"
+prefix="$2"
+configure="${3:-}"
+
+cd "$src"
+./autogen.sh
+eval "./configure --prefix='$prefix' $configure"
+make "-j$(nproc)"
+make install
diff --git a/.github/workflows/cross-library/scripts/check-break.sh b/.github/workflows/cross-library/scripts/check-break.sh
new file mode 100755
index 0000000000..28ac1b9f0e
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/check-break.sh
@@ -0,0 +1,105 @@
+#!/usr/bin/env bash
+#
+# Decide whether an intentional wolfSSL break of a downstream product has been
+# DECLARED in a commit message, so the cross-library job can tell an accountable
+# break from an accidental one.
+#
+# ONLY a break of a product's latest RELEASE TAG can be declared, i.e. a
+# released, immutable version that wolfSSL is intentionally dropping
+# compatibility with. The declaring commit names that exact tag:
+#
+#     breaks-<product>=<tag>      e.g.  breaks-wolfssh=v1.5.0-stable
+#
+# There is deliberately no shorthand (no latest/head/*), and there is NO way to
+# declare a break of a product's master/HEAD: if wolfSSL master breaks a
+# product's master, the PR must be reworked or the product's master fixed, and
+# it is never waived. (The engine only consults this script for the latest-tag leg.)
+#
+# The scan window is "the release tag BEFORE the last one .. HEAD", i.e. the
+# last TWO wolfSSL release cycles. Two (not one) so that when wolfSSL cuts a new
+# release, a break declared in the prior cycle keeps being recognized for one
+# more cycle, giving the downstream product time to ship a fixed release before
+# PRs go red again for the known issue. Matching is case-insensitive.
+#
+# Exit 0 (prints the declaring commits) if the (product, ref) break is declared;
+# exit 1 otherwise. Requires full history + tags in the checkout
+# (actions/checkout fetch-depth: 0, fetch-tags: true).
+#
+# Usage: check-break.sh <product> <ref>
+
+set -uo pipefail
+
+product="$1"
+ref="$2"
+
+lc() { printf '%s' "$1" | tr '[:upper:]' '[:lower:]'; }
+ref_lc="$(lc "$ref")"
+
+# Fail LOUD, never fail open. This is a gate: if git cannot read the repository
+# (e.g. a container-job "dubious ownership" refusal, or a shallow/absent
+# checkout), every git call below returns nothing and the scan would silently
+# report "no break declared", turning an environment failure into a wrong
+# compatibility verdict. Refuse to run rather than answer from a broken repo.
+if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+    echo "check-break: ERROR: cannot read git history at '$(pwd)':" >&2
+    git rev-parse --is-inside-work-tree 1>&2 || true   # re-run to surface git's own message
+    echo "check-break: not a usable git checkout (dubious ownership in a container job, or missing history/tags)." >&2
+    exit 2
+fi
+
+# Window: the release tag BEFORE the last one .. HEAD (last two release cycles,
+# for the one-release grace period described above). We pick release tags by
+# version order, not commit ancestry: wolfSSL carries many non-release tags
+# (e.g. *-CHKIN, wolfEntropy*) that `git describe` would otherwise land on.
+# RELEASE_GLOB matches wolfSSL's release tags (vX.Y.Z-stable).
+RELEASE_GLOB='v*-stable'
+rel="$(git tag --merged HEAD --sort=-v:refname --list "$RELEASE_GLOB" 2>/dev/null)"
+# Line 2 = the release before the newest (our scan base). Fall back to the
+# newest (line 1) if only one exists, or full history if there are no release
+# tags (e.g. an unexpectedly shallow clone).
+base="$(printf '%s\n' "$rel" | sed -n '2p')"
+[ -n "$base" ] || base="$(printf '%s\n' "$rel" | sed -n '1p')"
+range="HEAD"
+[ -n "$base" ] && range="${base}..HEAD"
+
+# Diagnostics (to stderr, so they always show in the CI log). This is what makes
+# a "no break is declared" failure debuggable: it prints the scan window and the
+# actual commit messages/tokens check-break.sh is looking at. git stderr is NOT
+# suppressed here (unlike the scan below) so a real git failure, e.g. "dubious
+# ownership" of the workspace in a container job, surfaces instead of silently
+# looking like "no token found".
+{
+    echo "check-break: product='${product}' ref='${ref}'"
+    echo "check-break: release tags merged into HEAD (newest first):"
+    printf '%s\n' "$rel" | sed 's/^/    /'
+    echo "check-break: scan base='${base:-<root>}' range='${range}'"
+    echo "check-break: commit messages in range (hash subject):"
+    git log "$range" --no-merges --format='    %h %s' 2>&1 | sed -n '1,300p'
+    echo "check-break: breaks-${product}= tokens found in range:"
+    git log "$range" --no-merges --format='%B' 2>&1 \
+        | grep -ioaE "breaks-${product}=[^[:space:]]+" | sed 's/^/    /' \
+        || echo "    (none)"
+} >&2
+
+declared=0
+while IFS= read -r val; do
+    [ -z "$val" ] && continue
+    v="$(lc "$val")"
+    # A break target may ONLY be an exact release tag. Branch names and
+    # wildcards (head, master, main, latest, all, *) are never valid break
+    # targets and are ignored outright, so master/HEAD breaks are not waivable.
+    case "$v" in
+        head|master|main|latest|all|*'*'*) continue ;;
+    esac
+    [ "$v" = "$ref_lc" ] && declared=1
+done < <(git log "$range" --no-merges --format='%B' 2>/dev/null \
+            | grep -ioaE "breaks-${product}=[^[:space:]]+" \
+            | sed 's/^[^=]*=//')
+
+if [ "$declared" -eq 1 ]; then
+    echo "Declared break: '${product}' at '${ref}' is covered by a breaks-${product}= token (since ${base:-<root>}):"
+    git log "$range" --no-merges -i --grep="breaks-${product}=" \
+        --format='  %h %s (%an)' 2>/dev/null || true
+    exit 0
+fi
+exit 1
diff --git a/.github/workflows/cross-library/scripts/common.sh b/.github/workflows/cross-library/scripts/common.sh
new file mode 100755
index 0000000000..9887f87abb
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/common.sh
@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+#
+# Shared helpers for the wolfSSL cross-library compile checks.
+#
+# Each cross-library script builds a downstream wolfSSL product against a
+# locally-built, already-installed wolfSSL and confirms it COMPILES. There is
+# no runtime testing here (no `make check`): the goal is only to catch changes
+# in wolfSSL that would stop a product from compiling.
+#
+# Product-script interface (see wolfssh.sh etc.):
+#   <product>.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+#     -t <ref>   build that git ref (tag or branch)
+#     (no -t)    build HEAD of the repo's default branch (master or main,
+#                auto-detected, no guessing)
+
+set -euo pipefail
+
+# resolve_repo_url <repo>
+# Accept either "owner/repo" shorthand or a full git URL / scp-style remote and
+# echo a clonable URL.
+resolve_repo_url() {
+    local repo="$1"
+    case "$repo" in
+        *://*|git@*) printf '%s\n' "$repo" ;;
+        *)           printf 'https://github.com/%s.git\n' "$repo" ;;
+    esac
+}
+
+# default_branch <url>
+# Echo the remote's default branch (e.g. master or main). Falls back to master.
+default_branch() {
+    local url="$1" br
+    br="$(git ls-remote --symref "$url" HEAD 2>/dev/null \
+            | sed -n 's@^ref:[[:space:]]*refs/heads/\([^[:space:]]*\)[[:space:]]*HEAD$@\1@p')"
+    printf '%s\n' "${br:-master}"
+}
+
+# latest_tag <url>
+# Echo the highest version tag on the remote, or nothing if it has no tags.
+# Uses git's version sort (--sort=-v:refname), which is robust to a repo mixing
+# tag styles (e.g. wolfTPM has both "v4.0.0" and a legacy "v.1.8" that GNU
+# `sort -V` mis-orders to the top). sed picks line 1 without cutting git's pipe,
+# so `set -o pipefail` stays happy.
+latest_tag() {
+    local url="$1"
+    git ls-remote --tags --refs --sort='-v:refname' "$url" \
+        | sed -n '1s@.*refs/tags/@@p'
+}
+
+# Globals populated by _prepare, consumed by the build functions below.
+CL_INSTALL=""
+CL_REPO=""
+CL_SRC=""
+CL_REF=""
+CL_CONFIGURE=()
+
+# _prepare [-t <ref>] <wolfssl_install_dir> <repo> [configure...]
+# Parse args, resolve the ref (tag via -t, else default branch), shallow-clone
+# the product, and leave CWD inside the cloned tree.
+_prepare() {
+    local tag="" opt OPTIND=1
+    while getopts ":t:" opt; do
+        case "$opt" in
+            t) tag="$OPTARG" ;;
+            *) echo "usage: $0 [-t <ref>] <wolfssl_install_dir> <repo> [configure...]" >&2
+               exit 2 ;;
+        esac
+    done
+    shift $((OPTIND - 1))
+
+    CL_INSTALL="$1"; shift
+    CL_REPO="$1";    shift
+    CL_CONFIGURE=("$@")
+
+    local url
+    url="$(resolve_repo_url "$CL_REPO")"
+    CL_SRC="$(basename "$CL_REPO" .git)"
+
+    if [ -n "$tag" ]; then
+        CL_REF="$tag"
+    else
+        CL_REF="$(default_branch "$url")"
+    fi
+
+    echo "==> Building ${CL_REPO} @ ${CL_REF} against wolfSSL in ${CL_INSTALL}"
+    set -x
+    git clone --depth 1 --branch "$CL_REF" "$url" "$CL_SRC"
+    cd "$CL_SRC"
+    set +x
+}
+
+# cross_build_autotools [-t <ref>] <wolfssl_install_dir> <repo> [configure...]
+# Standard autotools product: configure --with-wolfssl and compile (no check).
+cross_build_autotools() {
+    _prepare "$@"
+    set -x
+    if [ -x ./autogen.sh ]; then
+        ./autogen.sh
+    fi
+    # Point the compiler/linker at the installed wolfSSL. --with-wolfssl alone
+    # is not enough for every product: some configure link-tests need -L to
+    # find -lwolfssl, and some example/app compiles need -I to find headers
+    # (e.g. wolfssl/options.h). rpath lets the built binaries run without
+    # LD_LIBRARY_PATH, and PKG_CONFIG_PATH covers products that probe pkg-config.
+    export PKG_CONFIG_PATH="${CL_INSTALL}/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}"
+    ./configure --with-wolfssl="$CL_INSTALL" "${CL_CONFIGURE[@]}" \
+        CPPFLAGS="-I${CL_INSTALL}/include" \
+        LDFLAGS="-L${CL_INSTALL}/lib -Wl,-rpath,${CL_INSTALL}/lib"
+    make "-j$(nproc)"
+    set +x
+}
diff --git a/.github/workflows/cross-library/scripts/latest-tag.sh b/.github/workflows/cross-library/scripts/latest-tag.sh
new file mode 100755
index 0000000000..ddc9930a9d
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/latest-tag.sh
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# Poll a product repo for its highest version tag (version-sorted) and echo it.
+# Used by the workflow to resolve the "latest release" matrix leg, which is then
+# passed to the product script as `-t <tag>`.
+#
+# Usage: latest-tag.sh <repo>   (repo: "owner/repo" or a full git URL)
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+
+url="$(resolve_repo_url "$1")"
+tag="$(latest_tag "$url")"
+if [ -z "$tag" ]; then
+    echo "no tags found for $1" >&2
+    exit 1
+fi
+printf '%s\n' "$tag"
diff --git a/.github/workflows/cross-library/scripts/resolve-ref.sh b/.github/workflows/cross-library/scripts/resolve-ref.sh
new file mode 100755
index 0000000000..cfb6550448
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/resolve-ref.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# Echo the git ref a product should be built at:
+#   mode=latest -> the highest version tag (polled)
+#   mode=head   -> the default branch (master/main, auto-detected)
+# Usage: resolve-ref.sh <repo> <mode>
+set -euo pipefail
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+
+repo="$1"; mode="$2"
+url="$(resolve_repo_url "$repo")"
+
+case "$mode" in
+    latest)
+        t="$(latest_tag "$url")"
+        [ -n "$t" ] || { echo "no tags found for $repo" >&2; exit 1; }
+        printf '%s\n' "$t" ;;
+    head)
+        default_branch "$url" ;;
+    *)
+        echo "resolve-ref: unknown mode '$mode' (expected 'head' or 'latest')" >&2
+        exit 2 ;;
+esac
diff --git a/.github/workflows/cross-library/scripts/wolfclu.sh b/.github/workflows/cross-library/scripts/wolfclu.sh
new file mode 100755
index 0000000000..71bc096c2a
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/wolfclu.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Compile-check wolfclu against a locally-built wolfSSL.
+# Usage: wolfclu.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+cross_build_autotools "$@"
diff --git a/.github/workflows/cross-library/scripts/wolfmqtt.sh b/.github/workflows/cross-library/scripts/wolfmqtt.sh
new file mode 100755
index 0000000000..88d1d1ad09
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/wolfmqtt.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Compile-check wolfmqtt against a locally-built wolfSSL.
+# Usage: wolfmqtt.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+cross_build_autotools "$@"
diff --git a/.github/workflows/cross-library/scripts/wolfpkcs11.sh b/.github/workflows/cross-library/scripts/wolfpkcs11.sh
new file mode 100755
index 0000000000..d6a52af654
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/wolfpkcs11.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Compile-check wolfpkcs11 against a locally-built wolfSSL.
+# Usage: wolfpkcs11.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+cross_build_autotools "$@"
diff --git a/.github/workflows/cross-library/scripts/wolfprovider.sh b/.github/workflows/cross-library/scripts/wolfprovider.sh
new file mode 100755
index 0000000000..c9e587d0be
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/wolfprovider.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# Compile-check wolfProvider against a locally-built wolfSSL.
+#
+# wolfProvider is an OpenSSL 3.x provider, so unlike the other products it also
+# needs OpenSSL dev headers/libs (installed via the caller's apt_packages, e.g.
+# libssl-dev) and an extra --with-openssl. NOTE: the exact flag set may need
+# tuning per release; adjust the caller's wolfssl_configure / product_configure.
+#
+# Usage: wolfprovider.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+
+_prepare "$@"
+set -x
+if [ -x ./autogen.sh ]; then
+    ./autogen.sh
+fi
+export PKG_CONFIG_PATH="${CL_INSTALL}/lib/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}"
+./configure --with-wolfssl="$CL_INSTALL" --with-openssl=/usr "${CL_CONFIGURE[@]}" \
+    CPPFLAGS="-I${CL_INSTALL}/include" \
+    LDFLAGS="-L${CL_INSTALL}/lib -Wl,-rpath,${CL_INSTALL}/lib"
+make "-j$(nproc)"
+set +x
diff --git a/.github/workflows/cross-library/scripts/wolfssh.sh b/.github/workflows/cross-library/scripts/wolfssh.sh
new file mode 100755
index 0000000000..3ee86826c9
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/wolfssh.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Compile-check wolfssh against a locally-built wolfSSL.
+# Usage: wolfssh.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+cross_build_autotools "$@"
diff --git a/.github/workflows/cross-library/scripts/wolftpm.sh b/.github/workflows/cross-library/scripts/wolftpm.sh
new file mode 100755
index 0000000000..521d73417b
--- /dev/null
+++ b/.github/workflows/cross-library/scripts/wolftpm.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# Compile-check wolftpm against a locally-built wolfSSL.
+# Usage: wolftpm.sh [-t <ref>] <wolfssl_install_dir> <repo> [product_configure...]
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=./common.sh
+. "$DIR/common.sh"
+cross_build_autotools "$@"
diff --git a/.github/workflows/cross-wolfclu.yml b/.github/workflows/cross-wolfclu.yml
new file mode 100644
index 0000000000..39aa09a5f2
--- /dev/null
+++ b/.github/workflows/cross-wolfclu.yml
@@ -0,0 +1,24 @@
+name: wolfCLU cross-library
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'release/**' ]
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  cross-library:
+    uses: ./.github/workflows/cross-library.yml
+    with:
+      product: wolfclu
+      repo: wolfSSL/wolfCLU
+      wolfssl_configure: --enable-wolfclu
+      product_configure: ''
+      script: wolfclu.sh
diff --git a/.github/workflows/cross-wolfmqtt.yml b/.github/workflows/cross-wolfmqtt.yml
new file mode 100644
index 0000000000..fcaf78475e
--- /dev/null
+++ b/.github/workflows/cross-wolfmqtt.yml
@@ -0,0 +1,25 @@
+name: wolfMQTT cross-library
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'release/**' ]
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  cross-library:
+    uses: ./.github/workflows/cross-library.yml
+    with:
+      product: wolfmqtt
+      repo: wolfSSL/wolfMQTT
+      # wolfMQTT needs --enable-base64encode; --enable-all covers it.
+      wolfssl_configure: --enable-all
+      product_configure: ''
+      script: wolfmqtt.sh
diff --git a/.github/workflows/cross-wolfpkcs11.yml b/.github/workflows/cross-wolfpkcs11.yml
new file mode 100644
index 0000000000..c321bef90d
--- /dev/null
+++ b/.github/workflows/cross-wolfpkcs11.yml
@@ -0,0 +1,28 @@
+name: wolfPKCS11 cross-library
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'release/**' ]
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  cross-library:
+    uses: ./.github/workflows/cross-library.yml
+    with:
+      product: wolfpkcs11
+      repo: wolfSSL/wolfPKCS11
+      # wolfPKCS11's documented wolfSSL build (see its README).
+      wolfssl_configure: >-
+        --enable-aescfb --enable-rsapss --enable-keygen --enable-pwdbased
+        --enable-scrypt
+        C_EXTRA_FLAGS="-DWOLFSSL_PUBLIC_MP -DWC_RSA_DIRECT -DHAVE_AES_ECB -DHAVE_AES_KEYWRAP"
+      product_configure: ''
+      script: wolfpkcs11.sh
diff --git a/.github/workflows/cross-wolfprovider.yml b/.github/workflows/cross-wolfprovider.yml
new file mode 100644
index 0000000000..ec686c2cbe
--- /dev/null
+++ b/.github/workflows/cross-wolfprovider.yml
@@ -0,0 +1,29 @@
+name: wolfProvider cross-library
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'release/**' ]
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  cross-library:
+    uses: ./.github/workflows/cross-library.yml
+    with:
+      product: wolfprovider
+      repo: wolfSSL/wolfProvider
+      # wolfProvider's documented wolfSSL build (see its scripts/utils-wolfssl.sh).
+      wolfssl_configure: >-
+        --enable-all-crypto --with-eccminsz=192 --with-max-ecc-bits=1024
+        --enable-opensslcoexist --enable-sha
+        CFLAGS="-DWC_RSA_NO_PADDING -DWOLFSSL_PUBLIC_MP -DHAVE_PUBLIC_FFDHE -DHAVE_FFDHE_6144 -DHAVE_FFDHE_8192 -DWOLFSSL_PSS_LONG_SALT -DWOLFSSL_PSS_SALT_LEN_DISCOVER -DRSA_MIN_SIZE=1024 -DWOLFSSL_OLD_OID_SUM"
+      product_configure: ''
+      script: wolfprovider.sh
+      apt_packages: libssl-dev
diff --git a/.github/workflows/cross-wolfssh.yml b/.github/workflows/cross-wolfssh.yml
new file mode 100644
index 0000000000..b08d42a6c7
--- /dev/null
+++ b/.github/workflows/cross-wolfssh.yml
@@ -0,0 +1,25 @@
+name: wolfSSH cross-library
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'release/**' ]
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  cross-library:
+    uses: ./.github/workflows/cross-library.yml
+    with:
+      product: wolfssh
+      repo: wolfSSL/wolfssh
+      # wolfSSH's own CI builds wolfSSL with --enable-all.
+      wolfssl_configure: --enable-all
+      product_configure: --enable-all
+      script: wolfssh.sh
diff --git a/.github/workflows/cross-wolftpm.yml b/.github/workflows/cross-wolftpm.yml
new file mode 100644
index 0000000000..ac946369bd
--- /dev/null
+++ b/.github/workflows/cross-wolftpm.yml
@@ -0,0 +1,24 @@
+name: wolfTPM cross-library
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'release/**' ]
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    branches: [ '*' ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  cross-library:
+    uses: ./.github/workflows/cross-library.yml
+    with:
+      product: wolftpm
+      repo: wolfSSL/wolfTPM
+      wolfssl_configure: --enable-wolftpm --enable-pkcallbacks --enable-keygen
+      product_configure: ''
+      script: wolftpm.sh