CVE-2026-54278CWE-409

AIOHTTP: Unread Compressed Request Bodies Bypass client_max_size During Cleanup

Medium · published June 22, 2026

CVSS v4.0
6.6
EPSS
0%
Percentile
41.4
In the wild
Unconfirmed
What it is

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, during cleanup it is possible for a compressed request body to be decompressed into memory in one chunk. An attacker may be able to send a compressed payload in specific situations that could be decompressed into memory, potentially leading to DoS (a zip bomb edge case). This vulnerability is fixed in 3.14.1.

The record
Technical detail
CVSS v4.0
6.6 · MEDIUM
Vector
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
EPSS
0.00493 · 41.4th percentile
Weakness
CWE-409 · Improper Handling of Highly Compressed Data (Data Amplification)
Published
2026-06-22T16:38Z
EPSS history
Timeline
  • 22 JUN 16:38Z
    AIOHTTP: Unread Compressed Request Bodies Bypass client_max_size During Cleanup
    cvelistv5