Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

4.6 · 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 · score source

EPSS

• CVE-2026-32947: 0.31% estimated exploitation activity in the next 30 days; percentile 23.92 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A vulnerability exists in the Community Tier of Harden-Runner that allows bypassing the egress-policy: block network restriction using DNS over HTTPS (DoH). Harden-Runner secures GitHub Actions workflows on runners by applying network policies, including an allowed-endpoints configuration that limits outbound traffic to specified domains and ports (e.g., github.com:443). In egress-policy: block mode, non-compliant connections are intercepted and denied. This vulnerability exploits DoH, a protocol that encapsulates DNS queries within HTTPS requests. By crafting a DNS query that embeds exfiltrated data as a subdomain (e.g., encoding the runner's hostname into a label), an attacker can route the request through a permitted HTTPS endpoint like dns.google (8.8.8.8's DoH service). The resolver processes the query and forwards it to the attacker's controlled domain, achieving exfiltration without directly accessing the blocked destination. This evades Harden-Runner's domain-based…

Published by the source

17 Mar 2026, 18:38 UTC

Last modified by the source

20 Mar 2026, 21:21 UTC

Source last checked

26 Oct 2026, 17:08 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-46g3-37rh-v698

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# Patch Next advisory brief: CVE-2026-32947

Advisory: Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)
IDs: CVE-2026-32947, GHSA-46g3-37rh-v698
Record: https://patchnext.com/advisories/cve-2026-32947 (revision 1, source checked 26 Oct 2026, 17:08 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: step-security/harden-runner 2.16.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- GitHub Actions step-security/harden-runner: affected <= 2.15.1; fixed in 2.16.0

## Suggested inspection (read-only)
- GitHub Actions step-security/harden-runner: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on step-security/harden-runner.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-46g3-37rh-v698 (GitHub-reviewed advisory GHSA-46g3-37rh-v698 lists affected ranges: GitHub Actions step-security/harden-runner >=0 <=2.15.1)

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