CVE-2026-34513: AIOHTTP: Denial of Service (DoS) via Unbounded DNS Cache in TCPConnector

Published Apr 1, 2026
·
Updated

### Summary An unbounded DNS cache could result in excessive memory usage possibly resulting in a DoS situation. ### Impact If an application makes requests to a very large number of hosts, this could cause the DNS cache to continue growing and slowly use excessive amounts of memory. ----- Patch: https://github.com/aio-libs/aiohttp/commit/c4d77c3533122be353b8afca8e8675e3b4cbda98

Affected Software

2 affected componentsFixes available
pip/aiohttp<=3.13.3
3.13.4
aiohttp aiohttp<3.13.4

Remediation

Patch Available

https://github.com/aio-libs/aiohttp/commit/c4d77c3533122be353b8afca8e8675e3b4cbda98

Patch Available

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-hcc4-c3v8-rx92

Event History

Apr 1, 2026
CVE Published
via MITRE·08:06 PM
Data Sourced
via MITRE·08:06 PM
DescriptionWeakness
Data Sourced
via NVD·09:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
Advisory Published
via GitHub·09:19 PM
Data Sourced
via GitHub·09:19 PM
DescriptionWeaknessAffected Software
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