CVE-2026-54273: AIOHTTP: HTTP/1 Pipelined Requests Queue Without Limit

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-22 · updated 2026-10-25
Weakness: CWE-770

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, no limit was present on the number of pipelined requests that could be queued. An attacker may be able to use pipelined requests to use excessive amounts of memory, potentially leading to DoS. This vulnerability is fixed in 3.14.1.

Affected products

aio-libs aiohttp: before 3.14.1 — fixed in 3.14.1
Pypi Aiohttp: before 3.14.1; 0.1, 0.10.0, 0.10.1, 0.10.2, 0.11.0, 0.12.0 (+301) — fixed in 3.14.1

How to fix

Upgrade to a fixed version: aio-libs aiohttp 3.14.1; Pypi Aiohttp 3.14.1. Check the vendor advisory for mitigations.

References

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