CVE-2026-34516: AIOHTTP: Multipart Header Size Bypass
Published Apr 1, 2026
·Updated
### Summary A response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. ### Impact Multipart headers were not subject to the same size restrictions in place for normal headers, potentially allowing substantially more data to be loaded into memory than intended. However, other restrictions in place limit the impact of this vulnerability. ----- Patch: https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f
Affected Software
2 affected componentsFixes available
pip/aiohttp<=3.13.3
3.13.4
aiohttp aiohttp<3.13.4
Remediation
Event History
Apr 1, 2026
CVE Published
via MITRE·08:13 PM
Data Sourced
via MITRE·08:13 PM
DescriptionWeakness
Data Sourced
via NVD·09:16 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·09:16 PM
RemedyAffected Software
Advisory Published
via GitHub·09:43 PM
Data Sourced
via GitHub·09:43 PM
DescriptionWeaknessAffected Software