Medium severity · published Apr 1, 2026
CVE-2026-34518
AIOHTTP: Cookie and Proxy-Authorization headers leaked on cross-origin redirect
5.3
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 27% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AI
aiohttp · aio-libs
< 3.13.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34518
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34518
Patch
https://github.com/aio-libs/aiohttp/commit/5351c980dcec7ad385730efdf4e1f4338b24fdb6
Release Notes
https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4
Patch
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-966j-vmvw-g2g9
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