AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, BodyPartReader.read_chunk() processing a multipart part with Content-Transfer-Encoding set to base64 keeps reading until the chunk length is a multiple of four without enforcing a byte limit. A short Content-Length or a long run of whitespace can cause one call to read the remaining body into memory before the size check or spin on the event loop. A remote attacker can send such a multipart request to a handler that reads multipart data and bypass client_max_size. This issue is fixed in version 3.14.4.

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Fri, 13 Nov 2026 22:15:00 +0000

Type Values Removed Values Added
First Time appeared Aio-libs
Aio-libs aiohttp
Vendors & Products Aio-libs
Aio-libs aiohttp

Fri, 13 Nov 2026 20:45:00 +0000

Type Values Removed Values Added
Description AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, BodyPartReader.read_chunk() processing a multipart part with Content-Transfer-Encoding set to base64 keeps reading until the chunk length is a multiple of four without enforcing a byte limit. A short Content-Length or a long run of whitespace can cause one call to read the remaining body into memory before the size check or spin on the event loop. A remote attacker can send such a multipart request to a handler that reads multipart data and bypass client_max_size. This issue is fixed in version 3.14.4.
Title AIOHTTP: Base64 multipart parts bypass client_max_size
Weaknesses CWE-400
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-11-13T20:30:19.198Z

Reserved: 2026-11-12T22:42:47.032Z

Link: CVE-2026-128127

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-13T21:17:44.460

Modified: 2026-11-13T22:11:32.147

Link: CVE-2026-128127

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-14T17:15:09Z

Weaknesses