CVE-2026-128128
AIOHTTP: WebSocket max_msg_size bypass via integer overflow
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the C WebSocket reader adds a declared frame length to the size of an already buffered partial message using signed 64-bit arithmetic. A length near two to the power of 63 can overflow, allowing the max_msg_size check to pass. A remote peer can send a small non-final fragment followed by an oversized message and cause unbounded memory consumption. The Python WebSocket reader is unaffected. This issue is fixed in version 3.14.4.
INFO
Published Date :
Nov. 13, 2026, 9:17 p.m.
Last Modified :
Nov. 13, 2026, 10:11 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update aiohttp to version 3.14.4.
- Apply relevant security patches.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-128128.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-128128 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-128128
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-128128 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-128128 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Nov. 13, 2026
Action Type Old Value New Value Added Description AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the C WebSocket reader adds a declared frame length to the size of an already buffered partial message using signed 64-bit arithmetic. A length near two to the power of 63 can overflow, allowing the max_msg_size check to pass. A remote peer can send a small non-final fragment followed by an oversized message and cause unbounded memory consumption. The Python WebSocket reader is unaffected. This issue is fixed in version 3.14.4. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-770 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/128xxx/CVE-2026-128128.json">CVE-2026-128128</a> Added Reference https://github.com/aio-libs/aiohttp/commit/8c8906a19f64e52ef6a7d44d65217eb3c5af413f Added Reference https://github.com/aio-libs/aiohttp/commit/8cfbe9abe5e11b84006a10f9bdf82bf607671dab Added Reference https://github.com/aio-libs/aiohttp/pull/13415 Added Reference https://github.com/aio-libs/aiohttp/pull/13494 Added Reference https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4 Added Reference https://github.com/aio-libs/aiohttp/security/advisories/GHSA-3rp8-rxj8-mvjw