CVE-2026-69244
Received Received - Intake

Out-of-Bounds Heap Read in AIOHTTP Client Parser

Vulnerability report for CVE-2026-69244, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-03

Last updated on: 2026-08-03

Assigner: GitHub, Inc.

Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.3, an out-of-bounds heap read could occur in the C response parser while building an error message for a malformed response. An attacker controlled server, or possibly an accidental response, could trigger a DoS in the client. The vulnerable path was error message construction in aiohttp/_http_parser.pyx, where an llhttp error-position pointer was used to build a snippet for malformed chunked responses and malformed request or response bytes at the buffer end. This issue is fixed in version 3.14.3.

CVSS Scores

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Meta Information

Published
2026-08-03
Last Modified
2026-08-03
Generated
2026-08-04
AI Q&A
2026-08-04
EPSS Evaluated
N/A
NVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
aiohttp aiohttp 3.14.3

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
CWE-400 The product does not properly control the allocation and maintenance of a limited resource.

Attack-Flow Graph

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Executive Summary

AIOHTTP before 3.14.3 has an out-of-bounds heap read in the C response parser during error message construction for malformed responses. An attacker-controlled server or accidental response could trigger a denial of service in the client by exploiting this issue in aiohttp/_http_parser.pyx.

Detection Guidance

Detection involves checking for vulnerable versions of aiohttp. Use pip to list installed packages: pip show aiohttp. If the version is below 3.14.3, the system is vulnerable. Monitor network traffic for malformed HTTP responses that may trigger the issue.

Impact Analysis

This vulnerability could allow an attacker to cause a denial of service in applications using affected versions of AIOHTTP by sending malformed responses. This may lead to application crashes or degraded performance.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a denial-of-service (DoS) issue in the AIOHTTP client library that could disrupt service availability but does not involve data breaches or unauthorized access.

Mitigation Strategies

Upgrade aiohttp to version 3.14.3 or later immediately. Use pip install --upgrade aiohttp. If upgrading is not possible, restrict network access to untrusted servers or implement strict input validation for HTTP responses.

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