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Fencer Vulns
medium 5.3

CVE-2026-25598 json

Bypassing Logging of Outbound Connections Using sendto, sendmsg, and sendmmsg in Harden-Runner (Community Tier)

published 2026-02-09 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-6837 , GHSA-cpmj-h4f6-r6pq

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits
0
none known

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.

Patch / fix

  • github-actions step-security/harden-runner 2.14.2
  • stepsecurity harden-runner 2.14.2

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-25598 updated cvss 4.3

harden-runner: Harden-Runner: Outbound network connections can evade audit logging via specific socket system calls.

  • Red Hat External Secrets Operator for Red Hat OpenShift external-secrets-operator/external-secrets-rhel9, external-secrets-operator/bitwarden-sdk-server-rhel9, external-secrets-operator/external-secrets-operator-rhel9, external-secrets-operator/external-secrets-operator-bundle Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9 Red Hat Multicluster Engine for Kubernetes multicluster-engine/work-rhel9, multicluster-engine/placement-rhel9, multicluster-engine/registration-rhel9, multicluster-engine/addon-manager-rhel9, multicluster-engine/registration-operator-rhel9 Red Hat OpenShift for Windows Containers openshift4-wincw/windows-machine-config-rhel9-operator, openshift4-wincw/windows-machine-config-operator-bundle
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift Pipelines openshift-pipelines/pipelines-nop-rhel8, openshift-pipelines/pipelines-events-rhel8, openshift-pipelines/pipelines-webhook-rhel8, openshift-pipelines/pipelines-resolvers-rhel8, openshift-pipelines/pipelines-controller-rhel8, openshift-pipelines/pipelines-entrypoint-rhel8, +2 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 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
CNA 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
github-actions step-security/harden-runner
<2.14.2
2.14.2

Affected products

  • step-security harden-runner

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.