chore(deps): update step-security/harden-runner action to v2.16.0 [security]

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
step-security/harden-runner	action	minor	v2.14.0 → v2.16.0

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Harden-Runner: Bypassing Logging of Outbound Connections Using sendto, sendmsg, and sendmmsg in Harden-Runner (Community Tier)

CVE-2026-25598 / GHSA-cpmj-h4f6-r6pq

More information

Details

Summary

A security vulnerability has been identified in the Harden-Runner GitHub Action (Community Tier) that allows outbound network connections to evade audit logging. Specifically, outbound traffic using the sendto, sendmsg, and sendmmsg socket system calls can bypass detection and logging when using egress-policy: audit.

Note: This vulnerability only affects audit mode. When using egress-policy: block, these connections are properly blocked. It requires the attacker to already have code execution capabilities within the GitHub Actions workflow (e.g., through workflow injection or compromised dependencies)

Affected Versions

• Harden-Runner Community Tier: All versions prior to v2.14.2
• Harden-Runner Enterprise Tier: NOT AFFECTED

Severity

Medium - This vulnerability affects audit logging capabilities but requires the attacker to already have code execution within the workflow.

Impact

When Harden-Runner is configured in audit mode (egress-policy: audit), attackers with the ability to execute arbitrary code in a workflow can:

• Send outbound network traffic without generating audit logs
• Bypass network monitoring for UDP-based communications

Important: This vulnerability requires the attacker to already have code execution capabilities within the GitHub Actions workflow (e.g., through workflow injection or compromised dependencies).

Technical Details

The vulnerability stems from incomplete monitoring coverage of certain socket-related system calls. Specifically, the following system calls can be used to send UDP traffic without triggering audit events:

• sendto()

• sendmsg()

• sendmmsg()

An attacker with code execution in a workflow can compile and execute native code that uses these system calls to establish covert communication channels.

Affected Users

This vulnerability ONLY affects users of the Harden-Runner Community Tier.

The Harden-Runner Enterprise Tier is NOT vulnerable to this bypass technique.

Remediation

For Community Tier Users

Upgrade to Harden-Runner v2.14.2 or later. This version includes fixes for the logging bypass vulnerability.

For Enterprise Tier Users

No action required. Enterprise tier customers are not affected by this vulnerability.

Credit

We would like to thank Devansh Batham for responsibly disclosing this vulnerability through our security reporting process. Devansh was communicative throughout the process and verified the fix before the fix before it was made public.

Severity

• CVSS Score: 6.0 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

References

• https://github.com/step-security/harden-runner/security/advisories/GHSA-cpmj-h4f6-r6pq
• https://github.com/step-security/harden-runner/commit/5ef0c079ce82195b2a36a210272d6b661572d83e
• https://github.com/step-security/harden-runner/releases/tag/v2.14.2
• https://nvd.nist.gov/vuln/detail/CVE-2026-25598
• https://github.com/advisories/GHSA-cpmj-h4f6-r6pq

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Egress Policy Bypass via DNS over TCP in Harden-Runner (Community Tier)

CVE-2026-32946 / GHSA-g699-3x6g-wm3g

More information

Details

Summary

A vulnerability exists in the Community Tier of Harden-Runner that allows bypassing the egress-policy: block network restriction using DNS queries over TCP.

Harden-Runner enforces egress policies on GitHub runners by filtering outbound connections at the network layer. When egress-policy: block is enabled with a restrictive allowed-endpoints list (e.g., only github.com:443), all non-compliant traffic should be denied. However, DNS queries over TCP, commonly used for large responses or fallback from UDP, are not adequately restricted. Tools like dig can explicitly initiate TCP-based DNS queries (+tcp flag) without being blocked.

This vulnerability requires the attacker to already have code execution capabilities within the GitHub Actions workflow.

The Enterprise Tier of Harden-Runner is not affected by this vulnerability.

Impact

When Harden-Runner is configured with egress-policy: block and a restrictive allowed-endpoints list, an attacker with existing code execution capabilities within a GitHub Actions workflow can bypass the egress block policy by initiating DNS queries over TCP to external resolvers. This allows outbound network communication that evades the configured network restrictions.

This vulnerability affects only the Community Tier. It requires the attacker to already have code execution capabilities within the GitHub Actions workflow.

Remediation

For Community Tier Users

Upgrade to Harden-Runner v2.16.0 or later.

For Enterprise Tier Users

No action required. Enterprise tier customers are not affected by this vulnerability.

Credit

We would like to thank Devansh Batham for responsibly disclosing this vulnerability through our security reporting process.

Severity

• CVSS Score: 4.6 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

References

• https://github.com/step-security/harden-runner/security/advisories/GHSA-g699-3x6g-wm3g
• https://github.com/step-security/harden-runner/releases/tag/v2.16.0
• https://nvd.nist.gov/vuln/detail/CVE-2026-32946
• https://github.com/advisories/GHSA-g699-3x6g-wm3g

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)

CVE-2026-32947 / GHSA-46g3-37rh-v698

More information

Details

Summary

A vulnerability exists in the Community Tier of Harden-Runner that allows bypassing the egress-policy: block network restriction using DNS over HTTPS (DoH).

Harden-Runner secures GitHub Actions workflows on runners by applying network policies, including an allowed-endpoints configuration that limits outbound traffic to specified domains and ports (e.g., github.com:443). In egress-policy: block mode, non-compliant connections are intercepted and denied.

This vulnerability exploits DoH, a protocol that encapsulates DNS queries within HTTPS requests. By crafting a DNS query that embeds exfiltrated data as a subdomain (e.g., encoding the runner's hostname into a label), an attacker can route the request through a permitted HTTPS endpoint like dns.google (8.8.8.8's DoH service). The resolver processes the query and forwards it to the attacker's controlled domain, achieving exfiltration without directly accessing the blocked destination. This evades Harden-Runner's domain-based filtering, as the initial HTTPS connection appears legitimate.

This vulnerability requires the attacker to already have code execution capabilities within the GitHub Actions workflow.

The Enterprise Tier of Harden-Runner is not affected by this vulnerability.

Impact

When Harden-Runner is configured with egress-policy: block and a restrictive allowed-endpoints list, an attacker with existing code execution capabilities within a GitHub Actions workflow can bypass the allowed domains check via DNS over HTTPS by proxying DNS queries through a permitted resolver (e.g., Google's DoH service). This allows data exfiltration even when allowed-endpoints is set to only whitelisted domains.

This vulnerability affects only the Community Tier. It requires the attacker to already have code execution capabilities within the GitHub Actions workflow.

Remediation

For Community Tier Users

Upgrade to Harden-Runner v2.16.0 or later.

For Enterprise Tier Users

No action required. Enterprise tier customers are not affected by this vulnerability.

Credit

We would like to thank Devansh Batham for responsibly disclosing this vulnerability through our security reporting process.

Severity

• CVSS Score: 4.6 / 10 (Medium)
• Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

References

• https://github.com/step-security/harden-runner/security/advisories/GHSA-46g3-37rh-v698
• https://github.com/step-security/harden-runner/releases/tag/v2.16.0
• https://nvd.nist.gov/vuln/detail/CVE-2026-32947
• https://github.com/advisories/GHSA-46g3-37rh-v698

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

step-security/harden-runner (step-security/harden-runner)

v2.16.0

Compare Source

What's Changed

• Updated action.yml to use node24
• Security fix: Fixed a medium severity vulnerability where the egress block policy could be bypassed via DNS over HTTPS (DoH) by proxying DNS queries through a permitted resolver, allowing data exfiltration even with a restrictive allowed-endpoints list. This issue only affects the Community Tier; the Enterprise Tier is not affected. See GHSA-46g3-37rh-v698 for details.
• Security fix: Fixed a medium severity vulnerability where the egress block policy could be bypassed via DNS queries over TCP to external resolvers, allowing outbound network communication that evades configured network restrictions. This issue only affects the Community Tier; the Enterprise Tier is not affected. See GHSA-g699-3x6g-wm3g for details.

Full Changelog: step-security/harden-runner@v2.15.1...v2.16.0

v2.15.1

Compare Source

What's Changed

• Fixes #​642 bug due to which post step was failing on Windows ARM runners
• Updates npm packages

Full Changelog: step-security/harden-runner@v2.15.0...v2.15.1

v2.15.0

Compare Source

What's Changed

Windows and macOS runner support

We are excited to announce that Harden Runner now supports Windows and macOS runners, extending runtime security beyond Linux for the first time.

Insights for Windows and macOS runners will be displayed in the same consistent format you are already familiar with from Linux runners, giving you a unified view of runtime activity across all platforms.

Full Changelog: step-security/harden-runner@v2.14.2...v2.15.0

v2.14.2

Compare Source

What's Changed

Security fix: Fixed a medium severity vulnerability where outbound network connections using sendto, sendmsg, and sendmmsg socket system calls could bypass audit logging when using egress-policy: audit. This issue only affects the Community Tier in audit mode; block mode and Enterprise Tier were not affected. See GHSA-cpmj-h4f6-r6pq for details.

Full Changelog: step-security/harden-runner@v2.14.1...v2.14.2

v2.14.1

Compare Source

What's Changed

1. In some self-hosted environments, the agent could briefly fall back to public DNS resolvers during startup if the system DNS was not yet available. This behavior was unintended for GitHub-hosted runners and has now been fixed to prevent any use of public DNS resolvers.

2. Fixed npm audit vulnerabilities

Full Changelog: step-security/harden-runner@v2.14.0...v2.14.1

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