CVEvulnerability

CVE-2026-32947

4.6 MEDIUM Published 2026-03-20 Modified 2026-06-17 Official page ↗
Status
Analyzed
Published
2026-03-20
Last modified
2026-06-17
Assigner
[email protected]
CVSS 4.0 ([email protected])
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
4.9 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
Weaknesses
CWE-693, CWE-863

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, a DNS over HTTPS (DoH) vulnerability allows attackers to bypass egress-policy: block network restrictions by tunneling exfiltrated data through permitted HTTPS endpoints like dns.google. The attack works by encoding sensitive data (e.g., the runner's hostname) as subdomains in DoH queries, which appear as legitimate HTTPS traffic to Harden-Runner's domain-based filtering but are ultimately forwarded to an attacker-controlled domain. This effectively enables data exfiltration without directly connecting to any blocked destination. Exploitation requires the attacker to already have code execution within the GitHub Actions workflow. The issue was fixed in version 2.16.0.

Affected configurations

• stepsecurity harden-runner (< 2.16.0)

Related

Weakness · CWE (2)

  • CWE-693 Protection Mechanism Failure weakness
  • CWE-863 Incorrect Authorization weakness

References