# CVE-2026-25598: Bypassing Logging of Outbound Connections Using sendto, sendmsg, and sendmmsg in Harden-Runner (Community Tier)

> Attackers can bypass outbound connection logging in Harden-Runner by using specific socket calls, evading audit trails in CI/CD environments.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Feb 2026
- **Updated:** 10 Feb 2026
- **Also known as:** GHSA-cpmj-h4f6-r6pq

## What is CVE-2026-25598?

CVE-2026-25598 is a medium-severity vulnerability in step-security harden-runner, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, 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. Prior to 2.14.2, a security vulnerability has been identified in the Harden-Runner GitHub Action (Community Tier) that allows outbound network connections to evade audit logging. Specifically, outbound traffic using the sendto, sendmsg, and sendmmsg socket system calls can bypass detection and logging when using egress-policy: audit. This vulnerability is fixed in 2.14.2.

Weakness: CWE-778 (Insufficient Logging)

## Which versions are affected by CVE-2026-25598?

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 | 2.14.2 |

Products: Stepsecurity Harden-Runner.

## How do I fix CVE-2026-25598?

Upgrade step-security/harden-runner to 2.14.2 or later.

## Is CVE-2026-25598 being exploited?

There is no known exploitation of CVE-2026-25598 in the wild and no public exploit code.

## Other vulnerabilities in step-security harden-runner

- [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)
- [CVE-2026-32947](https://insights.sbomify.com/CVE-2026-32947/): Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier) (medium 4.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25598 and fix it if it is affected.

What it is: CVE-2026-25598 is a medium-severity vulnerability in step-security harden-runner, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-25598 in the wild and no public exploit code.

Affected packages and fixed versions:
- step-security/harden-runner (GitHub Actions): affected all versions; fixed in 2.14.2

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-2026-25598/ (Markdown: https://insights.sbomify.com/CVE-2026-25598/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25598
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25598
- OSV: https://osv.dev/vulnerability/CVE-2026-25598

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25598/
Summaries are generated and may contain mistakes; the official description above is the record.