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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.003.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
aio-libs aiohttp affected
Version Status Constraints
< 3.14.3 affected —

No data.

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-cq5v-8q36-5273 AIOHTTP: Out-of-bounds heap read in C HTTP response parser error path (malformed chunked response)
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/aio-libs/aiohttp/commit/49f65d54150397892f7bcc4aae887767d51c322d cve-icon
https://github.com/aio-libs/aiohttp/pull/13223 cve-icon
https://github.com/aio-libs/aiohttp/releases/tag/v3.14.3 cve-icon
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-cq5v-8q36-5273 cve-icon
History

Tue, 04 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Mon, 03 Aug 2026 23:00:00 +0000

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

Mon, 03 Aug 2026 21:15:00 +0000

Type Values Removed Values Added
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.
Title AIOHTTP: Out-of-bounds heap read in C HTTP response parser error path (malformed chunked response)
Weaknesses CWE-125
CWE-400
CWE-416
References
Metrics cvssV4_0

{'score': 7.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-04T14:13:17.355Z

Reserved: 2026-08-03T19:54:19.852Z

Link: CVE-2026-69244

cve-icon Vulnrichment

Updated: 2026-08-04T14:13:13.978Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-04T09:45:03Z

Weaknesses