GHSA-7r3h-m5j6-3q42 is a medium-severity (CVSS 5) CWE-77 vulnerability in @actions/core. A fix is available for @actions/core — see the affected versions and patch details below.
@actions/core has Delimiter Injection Vulnerability in exportVariable
Exploitation Status
No confirmed exploitation observed yet
- 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-7r3h-m5j6-3q42.
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-7r3h-m5j6-3q42 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 377,333 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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@actions/corenpmDescription
Impact
The core.exportVariable function uses a well known delimiter that attackers can use to break out of that specific variable and assign values to other arbitrary variables. Workflows that write untrusted values to the GITHUB_ENV file may cause the path or other environment variables to be modified without the intention of the workflow or action author.
Patches
Users should upgrade to @actions/core v1.9.1.
Workarounds
If you are unable to upgrade the @actions/core package, you can modify your action to ensure that any user input does not contain the delimiter _GitHubActionsFileCommandDelimeter_ before calling core.exportVariable.
References
More information about setting-an-environment-variable in workflows
If you have any questions or comments about this advisory:
- Open an issue in
actions/toolkit
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @actions/core | all versions | 1.9.1npm install @actions/core@1.9.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @actions/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @actions/core to 1.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7r3h-m5j6-3q42 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-7r3h-m5j6-3q42 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-7r3h-m5j6-3q42. 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-7r3h-m5j6-3q42 in your dependencies?
O3 Security finds GHSA-7r3h-m5j6-3q42 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.