PyPI: aiohttp

CVE-2025-69228

Safety vulnerability ID: SFTY-20260105-77370

Safety legacy ID: pyup.io-83967

Affected versions of the aiohttp package are vulnerable to Denial of Service (DoS) due to improper enforcement of request size limits during multipart form parsing. The aiohttp aiohttp.web_request.Request.post() method in aiohttp/web_request.py iterates over multipart fields but (prior to the fix) resets its running byte counter per part rather than tracking the total size of the entire multipart form, allowing the aggregate payload to grow without being bounded by client_max_size.

Created at: Jan 14, 2026Updated at: Jan 14, 2026

Overview

AIOHTTP vulnerable to denial of service through large payloads

Advisory

Affected versions of the aiohttp package are vulnerable to Denial of Service (DoS) due to improper enforcement of request size limits during multipart form parsing. The aiohttp aiohttp.web_request.Request.post() method in aiohttp/web_request.py iterates over multipart fields but (prior to the fix) resets its running byte counter per part rather than tracking the total size of the entire multipart form, allowing the aggregate payload to grow without being bounded by client_max_size.

Affected Package

Affecting aiohttp package, versions
<3.13.3

Also affects

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How to Fix

Upgrade
aiohttp
to
3.13.3
or higher.

Mitigation and Workarounds

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Vulnerable Functions

Functions linked to known vulnerabilities.

Vulnerable function data is available for Enterprise customers

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Safety

Verified by Safety

Our Cybersecurity Intelligence Team reviewed this vulnerability. We combine public data with our own research to find issues not yet reported to public sources.

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