[AutoPR- Security] Patch kbd for CVE-2026-72693 [HIGH]

[Azure Linux Security Servicing Account (azurelinux-security)]

Auto Patch kbd for CVE-2026-72693.

Autosec pipeline run -> https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1183635&view=results

CVE-2026-72693 : Single Patch Backporter Pipeline Run -> https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1183640&view=results

Merge Checklist

All boxes should be checked before merging the PR (just tick any boxes which don't apply to this PR)

• The toolchain has been rebuilt successfully (or no changes were made to it)
• The toolchain/worker package manifests are up-to-date
• Any updated packages successfully build (or no packages were changed)
• Packages depending on static components modified in this PR (Golang, *-static subpackages, etc.) have had their Release tag incremented.
• Package tests (%check section) have been verified with RUN_CHECK=y for existing SPEC files, or added to new SPEC files
• All package sources are available
• cgmanifest files are up-to-date and sorted (./cgmanifest.json, ./toolkit/scripts/toolchain/cgmanifest.json, .github/workflows/cgmanifest.json)
• LICENSE-MAP files are up-to-date (./LICENSES-AND-NOTICES/SPECS/data/licenses.json, ./LICENSES-AND-NOTICES/SPECS/LICENSES-MAP.md, ./LICENSES-AND-NOTICES/SPECS/LICENSE-EXCEPTIONS.PHOTON)
• All source files have up-to-date hashes in the *.signatures.json files
• sudo make go-tidy-all and sudo make go-test-coverage pass
• Documentation has been updated to match any changes to the build system
• Ready to merge

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Summary

What does the PR accomplish, why was it needed?

• Auto Patch kbd for CVE-2026-72693 (HIGH).

Change Log

• CVE-2026-72693

Does this affect the toolchain?

YES/NO

Associated issues

• N/A

Links to CVEs

• https://nvd.nist.gov/vuln/detail/CVE-2026-72693

Test Methodology

• Pipeline build id: Buddy Build URL

[azure-pipelines]

Azure Pipelines:
There may be pipelines that require an authorized user to comment /azp run to run.

[v-swapsahu]

Patch analysis:

CVE-2026-72693:
Backported: Yes

The patch aligns with the upstream fix, with only minor adaptations for the older kbd 2.2.0 source.

The fix for CVE-2026-72693 makes openvt -u process matching more conservative. The previous implementation checked /proc//fd/0, which could identify the TTY device owner instead of the actual process owner. The patched implementation verifies both the process owner and its controlling terminal. It also refuses to pre-authenticate root.

Minor backport adaptations

• The older kbd source uses sprintf() for the removed /proc//fd/0 path, while the newer upstream source uses snprintf().
• The older man page uses .I formatting and terminates option descriptions with semicolons.
• The final current VT; punctuation is consistent with the kbd 2.2.0 man-page style. The preceding sentence is changed from -l; to -l. because it is no longer the final sentence in that option description.

Backport completeness
I do not see any missing upstream backport work in this AutoPR. The security-relevant source changes and documentation updates from the upstream fix are included.

Patch application

Due to a circular dependency involving a toolchain package, the PR Pipelines - Run PR-18466+kbd+unknown could not be completed successfully. Therefore, I am attesting the local build results for validation.