GHSA-3787-6prv-h9w3 is a low-severity (CVSS 3.9) Information Exposure vulnerability in undici. O3 Security confirms whether GHSA-3787-6prv-h9w3 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Undici proxy-authorization header not cleared on cross-origin redirect in fetch
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
undicinpmDescription
Impact
Undici already cleared Authorization headers on cross-origin redirects, but did not clear Proxy-Authorization headers.
Patches
This is patched in v5.28.3 and v6.6.1
Workarounds
There are no known workarounds.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | undici | all versions | 5.28.3 |
| 📦npm | undici | ≥ 6.0.0&&< 6.6.1 | 6.6.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for undici. 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 undici to 5.28.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3787-6prv-h9w3 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-3787-6prv-h9w3 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-3787-6prv-h9w3. 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-3787-6prv-h9w3 in your dependencies?
O3 detects GHSA-3787-6prv-h9w3 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.