Unknown · Harden-Runner · CVE-2026-32947
**Name of the Vulnerable Software and Affected Versions**
Harden-Runner versions 2.15.1 and below
**Description**
Harden-Runner, a CI/CD security agent functioning as an EDR for GitHub Actions runners, contains a DNS over HTTPS (DoH) issue. This allows attackers to circumvent network restrictions imposed by the `egress-policy: block` setting by tunneling exfiltrated data through permitted HTTPS endpoints, such as `dns.google`. The attack involves encoding sensitive data, like the runner's hostname, as subdomains within DoH queries. These queries appear as legitimate HTTPS traffic to Harden-Runner’s domain-based filtering but are ultimately forwarded to a domain controlled by the attacker, enabling data exfiltration without directly connecting to blocked destinations. Exploitation requires pre-existing code execution within the GitHub Actions workflow. The Enterprise Tier of Harden-Runner is not affected.
**Recommendations**
Upgrade to Harden-Runner version 2.16.0 or later.