What’s Vulnerable › Vulnerabilities

CVE-2026-50269: AIOHTTP: CRLF injection in multipart headers

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-22 · updated 2026-10-25
• Weakness: CWE-93

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 products

• aio-libs aiohttp: before 3.14.0 — fixed in 3.14.0
• Pypi Aiohttp: before 3.14.0; 0.1, 0.10.0, 0.10.1, 0.10.2, 0.11.0, 0.12.0 (+300) — fixed in 3.14.0

How to fix

Upgrade to a fixed version: aio-libs aiohttp 3.14.0; Pypi Aiohttp 3.14.0. Check the vendor advisory for mitigations.

References

• https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8
• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-m6qw-4cw2-hm4m

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