VulnerabilityAnalyzed
CVE-2026-34525
Prior to version 3.13.4, multiple Host headers were allowed in aiohttp.
MEDIUM 6.3EPSS 0.29%
Does this matter?
Lower severity and a low EPSS score (0.29%). Track it; it rarely justifies an emergency change on its own.
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, multiple Host headers were allowed in aiohttp. This issue has been patched in version 3.13.4.
- CVSS 4.0
- 6.3 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.29% probability · 21th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20, CWE-444
- Affected
- aiohttp/aiohttp
- Source
- security-advisories@github.com
References
- https://github.com/aio-libs/aiohttp/commit/53e2e6fc58b89c6185be7820bd2c9f40216b3000Patch
- https://github.com/aio-libs/aiohttp/commit/e00ca3cca92c465c7913c4beb763a72da9ed8349Patch
- https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4Release Notes
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-c427-h43c-vf67Patch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.