Bypassing Logging of Outbound Connections Using sendto, sendmsg, and sendmmsg in Harden-Runner (Community Tier)
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-863.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| step-security | harden-runner | before 2.14.2 | 2.14.2 | Patch available | CNA |
| — | step-security/harden-runner (GitHub Actions) | before 2.14.2 | 2.14.2 | Patch available | GHSA-cpmj-h4f6-r6pq |
- harden-runner Vendorstep-security Affected before 2.14.2 Fixed in 2.14.2 Patch available CNA
- step-security/harden-runner (GitHub Actions) Vendor— Affected before 2.14.2 Fixed in 2.14.2 Patch available GHSA-cpmj-h4f6-r6pq
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:stepsecurity:harden-runner:*:*:*:*:community:*:*:* | before 2.14.2 | Vulnerable | step-security |
- cpe:2.3:a:stepsecurity:harden-runner:*:*:*:*:community:*:*:* Versions before 2.14.2 Vulnerable ·step-security
Remediation
- Fix · CNA harden-runner (step-security) Fixed in 2.14.2
- Fix · GHSA-cpmj-h4f6-r6pq step-security/harden-runner (GitHub Actions) Fixed in 2.14.2 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| External Secrets Operator for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Gatekeeper 3 | Affected | No fix yet: Fix deferred |
| Multicluster Engine for Kubernetes | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift for Windows Containers | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- OpenShift Pipelines
Timeline
- 2026-10-02 Threatist record created from CVE-2026-25598
- 2026-10-03 Alias added: GHSA-cpmj-h4f6-r6pq
References
Advisory 2
More step-security Harden-runner vulnerabilities
- TI-2026-25395 Egress Policy Bypass via DNS over HTTPS (DoH) in Harden-Runner (Community Tier) CVSS 4.0MEDIUM 4.6
- TI-2026-25394 Egress Policy Bypass via DNS over TCP in Harden-Runner (Community Tier) CVSS 4.0MEDIUM 4.6
Sources
- CVE-2026-25598 · CVE Program
- CVE-2026-25598 · NVD
- FIRST EPSS
- GHSA-cpmj-h4f6-r6pq · GitHub Advisory Database · CC BY 4.0
- CVE-2026-25598 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences