GHSA-966j-vmvw-g2g9 is a medium-severity (CVSS 5.3) Information Exposure vulnerability in aiohttp. O3 Security confirms whether GHSA-966j-vmvw-g2g9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
AIOHTTP leaks Cookie and Proxy-Authorization headers on cross-origin redirect
Real-World Exposure
aiohttpReal-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
Summary
When following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers.
Impact
The Cookie and Proxy-Authorizations headers could contain sensitive information which may be leaked to an unintended party after following a redirect.
Patch: https://github.com/aio-libs/aiohttp/commit/5351c980dcec7ad385730efdf4e1f4338b24fdb6
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | aiohttp | all versions | 3.13.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aiohttp. 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 aiohttp to 3.13.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-966j-vmvw-g2g9 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-966j-vmvw-g2g9 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-966j-vmvw-g2g9. 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-966j-vmvw-g2g9 in your dependencies?
O3 detects GHSA-966j-vmvw-g2g9 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.