AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, aiohttp buffers all additional connection data received while a request marked for upgrade, such as a WebSocket handshake, is being handled, without a size limit or flow control. A remote attacker can stream data behind an upgrade request to a handler that does not immediately accept or reject the upgrade and cause unbounded memory consumption. This issue is fixed in version 3.14.4.
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History

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, aiohttp buffers all additional connection data received while a request marked for upgrade, such as a WebSocket handshake, is being handled, without a size limit or flow control. A remote attacker can stream data behind an upgrade request to a handler that does not immediately accept or reject the upgrade and cause unbounded memory consumption. This issue is fixed in version 3.14.4.
Title AIOHTTP: Unbounded buffering of data received during an upgrade request
Weaknesses CWE-770
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/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: 2026-11-13T21:25:19.830Z

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

Link: CVE-2026-128129

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-13T21:17:44.747

Modified: 2026-11-13T22:17:23.430

Link: CVE-2026-128129

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-14T08:30:09Z

Weaknesses