What’s Vulnerable › Vulnerabilities

CVE-2026-25598: Bypassing Logging of Outbound Connections Using sendto, sendmsg, and sendmmsg in Harden-Runner (Community Tier)

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-09 · updated 2026-06-17
• Weakness: CWE-778

Description

Harden-Runner is a CI/CD security agent that works like an EDR for GitHub Actions runners. Prior to 2.14.2, 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. This vulnerability is fixed in 2.14.2.

Affected products

• step-security harden-runner: before 2.14.2 — fixed in 2.14.2

How to fix

Upgrade to a fixed version: step-security harden-runner 2.14.2. Check the vendor advisory for mitigations.

References

• https://github.com/step-security/harden-runner/releases/tag/v2.14.2
• https://github.com/step-security/harden-runner/security/advisories/GHSA-cpmj-h4f6-r6pq

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