GHSA-xj87-mqvh-88w2
MEDIUMGHSA-xj87-mqvh-88w2 is a medium-severity (CVSS 4.8) CWE-140 vulnerability in fish-shop/syntax-check. O3 Security confirms whether GHSA-xj87-mqvh-88w2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
fish-shop/syntax-check Improper Neutralization of Delimiters
Blast Radius
fish-shop/syntax-checkReal-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
Improper neutralisation of delimiters in the pattern input (specifically the command separator ; and command substitution characters ( and )) mean that arbitrary command injection is possible by modification of the input value used in a workflow. This has the potential for exposure or exfiltration of sensitive information from the workflow runner, such as might be achieved by sending environment variables to an external entity.
Patches
As of this writing, the issue has been patched for versions in the v1.x.x release series in release v1.6.12 (also tagged as v1.6 and v1). The latest available release v2.0.0 also includes a corresponding patch (also tagged as v2.0 and v2).
Users should upgrade to at least the patched version v1.6.12 or preferably the latest available version v2.0.0. Workflows that use the action ref v1 will automatically receive the patched version v1.6.12 in future workflow runs.
Patch summary:
| Release series | Patched tags | Patched commit hashes |
|---|---|---|
1.x.x | v1.6.12, v1.6, v1 | 91e6817c48ad475542fe4e78139029b036a53b03 |
2.x.x | v2.0.0, v2.0, v2 | c2cb11395e21119ff8d6e7ea050430ee7d6f49ca |
Workarounds
Is it recommended that users update to the patched version v1.6.12 or the latest release version v2.0.0, however remediation may be possible through careful control of workflows and the pattern input value used by this action.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | fish-shop/syntax-check | all versions | 1.6.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fish-shop/syntax-check. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update fish-shop/syntax-check to 1.6.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xj87-mqvh-88w2 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 pinpoints whether GHSA-xj87-mqvh-88w2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-xj87-mqvh-88w2. 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-xj87-mqvh-88w2 in your dependencies?
O3 detects GHSA-xj87-mqvh-88w2 across GitHub Actions dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.