aio-libs aiohttp up to 3.14.0 C Parser allocation of resources

Summaryinfo

A vulnerability, which was classified as problematic, has been found in aio-libs aiohttp up to 3.14.0. Impacted is an unknown function of the component C Parser. This manipulation causes allocation of resources. This vulnerability is handled as CVE-2026-54277. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in aio-libs aiohttp up to 3.14.0. It has been declared as problematic. Affected by this vulnerability is an unknown functionality of the component C Parser. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. As an impact it is known to affect availability. The summary by CVE is:

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, it is possible to bypass the max_line_size check in parts of an HTTP request in the C parser. If using the optimised C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS. This vulnerability is fixed in 3.14.1.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-54277 since 06/12/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 3.14.1 eliminates this vulnerability. Applying the patch 5ab61bb4cd88f19b712f12c7c9295fe262bf804d 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.

Be aware that VulDB is the high quality 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
• 3.14.0

License

• open-source

Website

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

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