CVE-2026-32946 Egress Policy Bypass via DNS over TCP in Harden-Runner (Community Tier)
Attackers with code execution can bypass egress network restrictions by using TCP-based DNS queries, evading security controls in Harden-Runner.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32946?
CVE-2026-32946 is a medium-severity vulnerability in step-security harden-runner, published on 20 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-32946?
1 open source package ship an affected version, including step-security/harden-runner. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
step-security/harden-runner GitHub Actions | All versions | 2.16.0 |
Products include Stepsecurity Harden-Runner.
How do I fix CVE-2026-32946?
Upgrade step-security/harden-runner to 2.16.0 or later.
Is CVE-2026-32946 being exploited?
There is no known exploitation of CVE-2026-32946 in the wild and no public exploit code.
Other vulnerabilities in step-security harden-runner
Sources
Also known as GHSA-g699-3x6g-wm3g.