Vulnerability · Published Jan 5, 2026 · Assigned by GitHub_M
CVE-2025-69229AIOHTTP vulnerable to DoS through chunked messages
Medium 6.6
In plain English
A medium-severity resource allocation without limits in aiohttp from aio-libs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. In versions 3.13.2 and below, handling of chunked messages can result in excessive blocking CPU usage when receiving a large number of chunks. If an application makes use of the request.read() method in an endpoint, it may be possible for an attacker to cause the server to spend a moderate amount of blocking CPU time (e.g. 1 second) while processing the request. This could potentially lead to DoS as the server would be unable to handle other requests during that time. This issue is fixed in version 3.13.3.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | py3-aiohttp | 3.13.3-r0 | ALPINE-CVE-2025-69229 |
| Alpine:v3.24 | py3-aiohttp | 3.13.3-r0 | ALPINE-CVE-2025-69229 |
| Debian:12 | python-aiohttp | 3.8.4-1+deb12u2 | DEBIAN-CVE-2025-69229 |
| Debian:13 | python-aiohttp | 3.11.16-1+deb13u1 | DEBIAN-CVE-2025-69229 |
| Debian:14 | python-aiohttp | 3.13.3-1 | DEBIAN-CVE-2025-69229 |
| PyPI | aiohttp | 3.13.3 | PYSEC-2026-1106 |
| PyPI | aiohttp | 3.13.3 | GHSA-g84x-mcqj-x9qq |
| Ubuntu:25.10 | python-aiohttp | 3.11.16-1ubuntu0.1 | UBUNTU-CVE-2025-69229 |
Affected products (as reported)
Weakness: CWE-770 · 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