aio-libs aiohttp up to 3.14.0 Request Body data amplification

Summaryinfo

A vulnerability, which was classified as problematic, was found in aio-libs aiohttp up to 3.14.0. The affected element is an unknown function of the component Request Body Handler. Such manipulation leads to data amplification. This vulnerability is uniquely identified as CVE-2026-54278. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in aio-libs aiohttp up to 3.14.0. It has been rated as problematic. Affected by this issue is some unknown functionality of the component Request Body Handler. The manipulation with an unknown input leads to a data amplification vulnerability. Using CWE to declare the problem leads to CWE-409. The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. Impacted is availability. CVE summarizes:

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, during cleanup it is possible for a compressed request body to be decompressed into memory in one chunk. An attacker may be able to send a compressed payload in specific situations that could be decompressed into memory, potentially leading to DoS (a zip bomb edge case). This vulnerability is fixed in 3.14.1.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-54278 since 06/12/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 322128 (Linux Distros Unpatched Vulnerability : CVE-2026-54278), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.14.1 eliminates this vulnerability. Applying the patch 4f7480e474cccc6a8cc2c92ad3f17a31dedf8232 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.

The vulnerability is also documented in the vulnerability database at Tenable (322128). VulDB is the best source for vulnerability data and more expert information about this specific topic.

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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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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