GHSA-g85v-wf27-67xc is a high-severity (CVSS 8.8) OS Command Injection vulnerability in step-security/harden-runner. A fix is available for step-security/harden-runner — see the affected versions and patch details below.
Harden-Runner has a command injection weaknesses in `setup.ts` and `arc-runner.ts`
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-g85v-wf27-67xc.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-g85v-wf27-67xc plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
step-security/harden-runnerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Versions of step-security/harden-runner prior to v2.10.2 contain multiple command injection weaknesses via environment variables that could potentially be exploited under specific conditions. However, due to the current execution order of pre-steps in GitHub Actions and the placement of harden-runner as the first step in a job, the likelihood of exploitation is low as the Harden-Runner action reads the environment variable during the pre-step stage. There are no known exploits at this time.
Details
-
setup.ts:169 1 performs
execSyncwith a command that gets invoked after interpretation by the shell. This command includes an interpolatedprocess.env.USERvariable, which an attacker could modify (without actually creating a new user) to inject arbitrary shell expressions into thisexecSync. This may or may not be likely in practice, but I believe the hygienic way to perform the underlying operation is to useexecFileSyncor similar and bypass the underlying shell evaluation. -
setup.ts:229 2 has a nearly identical
execSyncto (1) above, but with$USERfor shell-level interpolation rather than string interpolation. However, this is still injectable and would be best replaced by anexecFileSync, per above. -
arc-runner:40-44 3 has an
execSyncwith multiple string interpolations. Most of these do not appear immediately injectible (since they appear to come from presumed trusted API responses), but the expansion ofgetRunnerTempDir()may be injectable due to its dependence on potentially attacker-controllable environment variables (e.g.RUNNER_TEMP). The underlying operation appears to be a trivial file copy, so this entire subprocess should in theory be replaceable with ordinary NodeJSfsAPI calls instead. -
arc-runner:53 4 demonstrates the same weakness, and has the same resolution as (3).
-
arc-runner:57 demonstrates the same weakness as (3) and (4), and has the same resolution.
-
arc-runner:61 demonstrates the same weakness as (3), (4), and (5), and has the same resolution.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | step-security/harden-runner | all versions | 2.10.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for step-security/harden-runner, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update step-security/harden-runner to 2.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g85v-wf27-67xc is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-g85v-wf27-67xc can be triaged on real exposure rather than presence alone.
Tailored to GHSA-g85v-wf27-67xc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-g85v-wf27-67xc in your dependencies?
O3 Security finds GHSA-g85v-wf27-67xc across GitHub Actions dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.