REDHAT-BUG-2427256: Medium severity pypi/aiohttp vulnerability

Published Jan 6, 2026
·
Updated

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.

Affected Software

1 affected component
pypi/aiohttp<=3.13.2

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade aiohttp to a version that resolves this vulnerability.

    Fixed in 3.13.3
  2. Compensating control

    If upgrades are not immediately possible, avoid running with Python optimizations enabled (do not use -O or PYTHONOPTIMIZE=1) when the application includes a handler that uses the Request.post() method.

Event History

Jan 6, 2026
Data Sourced
via Red Hat·12:01 AM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

What is the severity of REDHAT-BUG-2427256?

The severity of REDHAT-BUG-2427256 is classified as medium with a rating of 4.

2

How do I fix REDHAT-BUG-2427256?

To fix REDHAT-BUG-2427256, update AIOHTTP to version 3.13.3 or later where the vulnerability is addressed.

3

What type of attack does REDHAT-BUG-2427256 allow for?

REDHAT-BUG-2427256 allows for a Denial of Service (DoS) attack when processing a POST body.

4

What versions of AIOHTTP are affected by REDHAT-BUG-2427256?

AIOHTTP versions 3.13.2 and below are affected by REDHAT-BUG-2427256.

5

What conditions exacerbate the impact of REDHAT-BUG-2427256?

The impact of REDHAT-BUG-2427256 is exacerbated when optimizations are enabled, using flags like -O or PYTHONOPTIMIZE=1.

Contact

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