GHSA-4x5r-pxfx-6jf8
LOWGHSA-4x5r-pxfx-6jf8 is a low-severity (CVSS 3.2) Path Traversal vulnerability in @babel/core. O3 Security confirms whether GHSA-4x5r-pxfx-6jf8 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
@babel/core: Arbitrary File Read via sourceMappingURL Comment
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@babel/corenpmDescription
Impact
Using @babel/core to compile maliciously crafted code can allow ab attacker to read any source map from the system that is running Babel, if these conditions are all true:
- the attacker controls the input source code
- the attacker can read the output source code
- the attacker knows the path of the source map file that they want to read
Users that only compile trusted code are not impacted.
Patches
The vulnerability has been fixed in @babel/[email protected] and @babel/[email protected].
Workarounds
Callers can mitigate the issue without upgrading by setting inputSourceMap: false in their Babel options.
Callers can also manually extract the #sourceMappingURL comment from the input source code, validate whether the source map that it links to is allowed to be read, and if it is pass an object to inputSourceMap (passing false when it's not).
Credits
Thanks Teodor-Cristian Radoi for reporting the vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @babel/core | ≥ 8.0.0-alpha.0&&< 8.0.0-rc.6 | 8.0.0-rc.6 |
| 📦npm | @babel/core | all versions | 7.29.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @babel/core. 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 @babel/core to 8.0.0-rc.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4x5r-pxfx-6jf8 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-4x5r-pxfx-6jf8 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-4x5r-pxfx-6jf8. 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-4x5r-pxfx-6jf8 in your dependencies?
O3 detects GHSA-4x5r-pxfx-6jf8 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.