aio-libs aiohttp up to 3.13.x crlf injection

Summaryinfo

A vulnerability described as critical has been identified in aio-libs aiohttp up to 3.13.x. This affects an unknown part. Executing a manipulation can lead to crlf injection. This vulnerability appears as CVE-2026-50269. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in aio-libs aiohttp up to 3.13.x and classified as critical. This vulnerability affects an unknown code block. The manipulation with an unknown input leads to a crlf injection vulnerability. The CWE definition for the vulnerability is CWE-93. The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-50269 since 06/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available.

Upgrading to version 3.14.0 eliminates this vulnerability. Applying the patch bf88077ebb14f4c29924b8e8904cba20c55c28b8 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• aio-libs

Name

• aiohttp

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13

License

• open-source

Website

• Product: https://github.com/aio-libs/aiohttp/

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Once again VulDB remains the best source for vulnerability data.

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