CVE-2026-32946 (GCVE-0-2026-32946)

Vulnerability from cvelistv5 – Published: 2026-03-20 03:58 – Updated: 2026-03-20 15:47
VLAI?
Title
Egress Policy Bypass via DNS over TCP in Harden-Runner (Community Tier)
Summary
Harden-Runner is a CI/CD security agent that works like an EDR for GitHub Actions runners. In versions 2.15.1 and below, the Harden-Runner that allows bypass of the egress-policy: block network restriction using DNS queries over TCP. Egress policies are enforced 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 issue has been fixed in version 2.16.0.
Severity ?
4.6 (Medium)
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
CWE
  • CWE-693 - Protection Mechanism Failure
  • CWE-863 - Incorrect Authorization
Assigner
References
Impacted products
Vendor Product Version
step-security harden-runner Affected: < 2.16.0
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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