Vulnerability · Published Jun 22, 2026 · Assigned by GitHub_M
CVE-2026-50269AIOHTTP: CRLF injection in multipart headers
Low 2.7
In plain English
A low-severity security flaw 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 0.5% (higher than 45% 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. Prior to 3.14.0, attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar. In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request. This vulnerability is fixed in 3.14.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-aiohttp | 3.8.4-1+deb12u2 | DEBIAN-CVE-2026-50269 |
| Debian:13 | python-aiohttp | no fix listed | DEBIAN-CVE-2026-50269 |
| Debian:14 | python-aiohttp | 3.14.0-1 | DEBIAN-CVE-2026-50269 |
| PyPI | aiohttp | 3.14.0 | PYSEC-2026-2106 |
| PyPI | aiohttp | 3.14.0 | GHSA-m6qw-4cw2-hm4m |
| Ubuntu:25.10 | python-aiohttp | no fix listed | UBUNTU-CVE-2026-50269 |
| Ubuntu:26.10 | python-aiohttp | no fix listed | UBUNTU-CVE-2026-50269 |
Affected products (as reported)
Weakness: CWE-93, CWE-113 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U