CVE-2026-128128
Received Received - Intake

Memory Exhaustion in AIOHTTP via WebSocket Frame Length

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-11-13
Last Modified
2026-11-13
Generated
2026-11-13
AI Q&A
2026-11-13
EPSS Evaluated
N/A
NVD
CVE-2026-128128
EUVD
EUVD-2026-125760

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
aiohttp aiohttp to 3.14.4 (exc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

AIOHTTP before 3.14.4 has a flaw in its C WebSocket reader where frame length calculations use signed 64-bit arithmetic. This can cause an integer overflow when a large length value is added to a buffered partial message. The overflow bypasses the max_msg_size check, allowing an attacker to send a small fragment followed by an oversized message. This leads to excessive memory consumption.

Detection Guidance

This vulnerability can be detected by checking the version of aiohttp installed on your system. Run 'pip show aiohttp' to see the installed version. If it is below 3.14.4, your system is vulnerable.

Impact Analysis

This vulnerability can be exploited remotely without authentication. An attacker could send specially crafted WebSocket messages to consume excessive server memory, potentially causing denial-of-service conditions or system crashes. Services relying on AIOHTTP for WebSocket communication are at risk.

Mitigation Strategies

Upgrade aiohttp to version 3.14.4 or later immediately. Use the command 'pip install --upgrade aiohttp' to update. Ensure all dependencies are compatible with the new version.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-128128. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart

Security Radar

News mentioning this vulnerability
Loading related security news...