GHSA-6q4m-7476-932w is a high-severity (CVSS 8.8) CWE-77 vulnerability in rlespinasse/github-slug-action. 1 public exploit reference exists, so weaponization risk is real. A fix is available for rlespinasse/github-slug-action — see the affected versions and patch details below.
github-slug-action vulnerable to arbitrary code execution
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-6q4m-7476-932w.
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-6q4m-7476-932w 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 377,166 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
rlespinasse/github-slug-actionReal-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
Impact
This action uses the github.head_ref parameter in an insecure way.
This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. (Note that first-time PR requests will not be run - but the attacker can submit a valid PR before submitting an invalid PR). This can be used to execute code on the GitHub runners (potentially use it for crypto-mining, and waste your resources) and to exfiltrate any secrets you use in the CI pipeline.
Patches
Pass the variable as an environment variable and then use the environment variable instead of substituting it directly.
Patched action is available on tag v4, tag v4.4.1, and any tag beyond.
Workarounds
No workaround is available if impacted, please upgrade the version
ℹ️ v3 and v4 are compatibles.
References
Here is a set of blog posts by Github's security team explaining this issue.
Thanks
Thanks to the team of researchers from Purdue University, who are working on finding vulnerabilities in CI/CD configurations of open-source software. Their tool detected this security vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | rlespinasse/github-slug-action | ≥ 4.0.0&&< 4.4.1 | 4.4.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rlespinasse/github-slug-action, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rlespinasse/github-slug-action to 4.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6q4m-7476-932w 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-6q4m-7476-932w can be triaged on real exposure rather than presence alone.
Tailored to GHSA-6q4m-7476-932w. 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-6q4m-7476-932w in your dependencies?
O3 Security finds GHSA-6q4m-7476-932w across GitHub Actions dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.