GHSA-v845-jxx5-vc9f
MEDIUM`Cookie` HTTP header isn't stripped on cross-origin redirects
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.
Blast Radius
urllib3🐍urllib3Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
urllib3 doesn't treat the Cookie HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a Cookie header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.
Users must handle redirects themselves instead of relying on urllib3's automatic redirects to achieve safe processing of the Cookie header, thus we decided to strip the header by default in order to further protect users who aren't using the correct approach.
Affected usages
We believe the number of usages affected by this advisory is low. It requires all of the following to be true to be exploited:
- Using an affected version of urllib3 (patched in v1.26.17 and v2.0.6)
- Using the
Cookieheader on requests, which is mostly typical for impersonating a browser. - Not disabling HTTP redirects
- Either not using HTTPS or for the origin server to redirect to a malicious origin.
Remediation
- Upgrading to at least urllib3 v1.26.17 or v2.0.6
- Disabling HTTP redirects using
redirects=Falsewhen sending requests. - Not using the
Cookieheader.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | urllib3 | ≥ 2.0.0&&< 2.0.6 | 2.0.6 |
| 🐍PyPI | urllib3 | all versions | 1.26.17 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for urllib3. 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 urllib3 to 2.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v845-jxx5-vc9f 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-v845-jxx5-vc9f 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-v845-jxx5-vc9f. 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-v845-jxx5-vc9f in your dependencies?
O3 detects GHSA-v845-jxx5-vc9f across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.