CVE-2026-54277AIOHTTP: C HTTP Parser Bypasses max_line_size for Fragmented Lines

Description

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-63hw-fmq6-xxg2 Vendor Advisory
• https://github.com/aio-libs/aiohttp/commit/5ab61bb4cd88f19b712f12c7c9295fe262bf804d Patch