CVE-2026-25598
Published: 09 February 2026
Summary
CVE-2026-25598 is a medium-severity Insufficient Logging (CWE-778) vulnerability in Stepsecurity Harden-Runner. Its CVSS base score is 6.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Disable or Modify Tools (T1685); ranked at the 23.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-6837
Vulnerability details
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.…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Bypass of egress audit logging via unmonitored syscalls directly impairs the Harden-Runner defensive tool, enabling undetected outbound activity.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Audit policy requires defining and implementing logging of security-relevant events, directly reducing insufficient logging.
Providing proof of performed actions necessitates sufficient logging of security-relevant events with attribution details.
Retaining audit records for a defined period ensures security-relevant events remain available for after-the-fact investigations, directly mitigating the risk that attackers can hide actions due to missing or purged log data.
Directly requires generation of audit records for specified events, preventing the absence of logging that allows undetected malicious activity.
Directly implements detailed session logging to address the weakness of insufficient logging.
Provides alternate logging mechanism to maintain audit trails when primary capability fails, directly reducing insufficient logging.
Employing coordination mechanisms ensures consistent and sufficient logging practices are applied when audit information crosses organizational boundaries.
This control requires identifying, specifying, and justifying event types for logging with a focus on adequacy for post-incident investigations, directly mitigating insufficient logging.