What is CVE-2026-54273?

CVE-2026-54273 is a high-severity vulnerability in Aiohttp, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-06-22.

How severe is CVE-2026-54273?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Aiohttp

CVE-2026-54273

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.

Published 2026-06-22 · last modified 2026-06-26.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (39.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 39.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

Aiohttp
Aio-Libs Aiohttp — versions < 3.14.1

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

github.com/aio-libs/aiohttp/security/advisories/GHSA-4fvr-rgm6-gqmc (Third Party Advisory)
github.com/aio-libs/aiohttp/commit/dfdfa9d5aad5d21f91c79fb2ceeba0f8046cb6cf (Patch)

Frequently asked questions

What is CVE-2026-54273?: CVE-2026-54273 is a high-severity vulnerability in Aiohttp, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-06-22.
How severe is CVE-2026-54273?: High severity. CVSS v3 base score is 7.5 out of 10.