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

> Attackers with code execution can bypass network egress restrictions in Harden-Runner by exfiltrating data via DNS over HTTPS tunnels.

- **Severity:** Medium 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`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Mar 2026
- **Updated:** 20 Mar 2026
- **Also known as:** GHSA-46g3-37rh-v698

## What is CVE-2026-32947?

CVE-2026-32947 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, 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.

Weakness: CWE-863 (Incorrect Authorization), CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-32947?

1 open source package ship an affected version, including step-security/harden-runner. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `step-security/harden-runner` | GitHub Actions | All versions | 2.16.0 |

Products: Stepsecurity Harden-Runner.

## How do I fix CVE-2026-32947?

Upgrade step-security/harden-runner to 2.16.0 or later.

## Is CVE-2026-32947 being exploited?

There is no known exploitation of CVE-2026-32947 in the wild and no public exploit code.

## Other vulnerabilities in step-security harden-runner

- [CVE-2026-25598](https://insights.sbomify.com/CVE-2026-25598/): Bypassing Logging of Outbound Connections Using sendto, sendmsg, and sendmmsg in Harden-Runner (Community Tier) (medium 6.3)
- [CVE-2026-32946](https://insights.sbomify.com/CVE-2026-32946/): Egress Policy Bypass via DNS over TCP in Harden-Runner (Community Tier) (medium 4.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-32947 and fix it if it is affected.

What it is: CVE-2026-32947 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.
Exploitation: There is no known exploitation of CVE-2026-32947 in the wild and no public exploit code.

Affected packages and fixed versions:
- step-security/harden-runner (GitHub Actions): affected all versions; fixed in 2.16.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-32947/ (Markdown: https://insights.sbomify.com/CVE-2026-32947/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32947
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32947
- OSV: https://osv.dev/vulnerability/CVE-2026-32947

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-32947/
Summaries are generated and may contain mistakes; the official description above is the record.