CVE-2026-34518AIOHTTP: Cookie and Proxy-Authorization headers leaked on cross-origin redirect

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, when following redirects to a different origin, aiohttp drops the Authorization header, but retains the Cookie and Proxy-Authorization headers. This issue has been patched in version 3.13.4.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-966j-vmvw-g2g9 PatchVendor Advisory
• https://github.com/aio-libs/aiohttp/commit/5351c980dcec7ad385730efdf4e1f4338b24fdb6 Patch
• https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4 Release Notes