GHSA-g3cq-j2xw-wf74: aiohttp (CVE-2026-54278)

aiohttp: Unread Compressed Request Bodies Bypass client_max_size During Cleanup

CVSS 6.6 MediumEPSS 0.0049 · 42nd percentile

Published by the GitHub Advisory Database at 15 Jun 2026, 20:09 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
aiohttp	PyPI	<3.14.1	3.14.1

Identifiers

GHSA-g3cq-j2xw-wf74 · CVE-2026-54278 · PYSEC-2026-2111

Weakness (CWE)

CWE-409

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Versions of aiohttp before 3.14.1 are vulnerable. During cleanup, a compressed request body can be decompressed into memory in one chunk, letting an attacker send a crafted compressed payload that may cause denial of service, similar to a zip bomb. Upgrade to aiohttp 3.14.1 or later. If upgrading is not possible, disable compression.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.6	Medium	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0049, the 42nd percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:11 UTC First seen by agentprime
31 Oct 2026, 14:11 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.