How severe is GHSA-cpmj-h4f6-r6pq?

No CVSS score has been assigned to GHSA-cpmj-h4f6-r6pq yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-cpmj-h4f6-r6pq?

GHSA-cpmj-h4f6-r6pq affects the following packages: step-security/harden-runner (GitHub Actions). Ecosystems affected: GitHub Actions.

How do I fix GHSA-cpmj-h4f6-r6pq?

Update step-security/harden-runner to 2.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cpmj-h4f6-r6pq is resolved across your whole dependency graph.

How do I detect GHSA-cpmj-h4f6-r6pq in my GitHub Actions dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for step-security/harden-runner. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-cpmj-h4f6-r6pq if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-cpmj-h4f6-r6pq?

O3 pinpoints whether GHSA-cpmj-h4f6-r6pq is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-cpmj-h4f6-r6pq actively exploited in the wild?

No public exploit code has been indexed for GHSA-cpmj-h4f6-r6pq yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-cpmj-h4f6-r6pq?

GHSA-cpmj-h4f6-r6pq has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-cpmj-h4f6-r6pq?

GHSA-cpmj-h4f6-r6pq is classified as CWE-778 (CWE-778). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-cpmj-h4f6-r6pq published, and has it been updated?

GHSA-cpmj-h4f6-r6pq was published on February 9, 2026 and was last updated on February 22, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 GitHub Actions

GHSA-cpmj-h4f6-r6pq

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

Also known asCVE-2026-25598

Published

Feb 9, 2026

Updated

Feb 22, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk23th percentile+0.29%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

📦step-security/harden-runner

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦GitHub Actions	`step-security/harden-runner`	all versions	2.14.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for step-security/harden-runner. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update step-security/harden-runner to 2.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cpmj-h4f6-r6pq is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-cpmj-h4f6-r6pq is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-cpmj-h4f6-r6pq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## 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 i

O3 Security · Impact-Aware SCA

Is GHSA-cpmj-h4f6-r6pq in your dependencies?

O3 detects GHSA-cpmj-h4f6-r6pq across GitHub Actions dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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