aio-libs aiohttp up to 3.13.2 Message Request.post infinite loop

Summaryinfo

A vulnerability was found in aio-libs aiohttp up to 3.13.2. It has been classified as problematic. Affected by this vulnerability is the function Request.post of the component Message Handler. Performing a manipulation results in infinite loop. This vulnerability was named CVE-2025-69227. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in aio-libs aiohttp up to 3.13.2. It has been classified as critical. This affects the function Request.post of the component Message Handler. The manipulation with an unknown input leads to a infinite loop vulnerability. CWE is classifying the issue as CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. This is going to have an impact on availability. The summary by CVE is:

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Versions 3.13.2 and below allow for an infinite loop to occur when assert statements are bypassed, resulting in a DoS attack when processing a POST body. If optimizations are enabled (-O or PYTHONOPTIMIZE=1), and the application includes a handler that uses the Request.post() method, then an attacker may be able to execute a DoS attack with a specially crafted message. This issue is fixed in version 3.13.3.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2025-69227 since 12/29/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 281879 (Linux Distros Unpatched Vulnerability : CVE-2025-69227), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.13.3 eliminates this vulnerability. Applying the patch bc1319ec3cbff9438a758951a30907b072561259 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 databases at CNNVD (CNNVD-202601-958) and Tenable (281879). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• aio-libs

Name

• aiohttp

Version

• 3.13.0
• 3.13.1
• 3.13.2

License

• open-source

Website

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

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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