Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.
Published: 2026-04-01
Score: 6.6 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service
Action: Patch
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-m5qp-6w8w-w647 AIOHTTP has a Multipart Header Size Bypass
History

Wed, 15 Apr 2026 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Aiohttp
Aiohttp aiohttp
CPEs cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*
Vendors & Products Aiohttp
Aiohttp aiohttp

Sat, 04 Apr 2026 05:00:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Thu, 02 Apr 2026 20:30:00 +0000

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

Thu, 02 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Moderate


Wed, 01 Apr 2026 23:45:00 +0000

Type Values Removed Values Added
Description AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.
Title AIOHTTP: Multipart Header Size Bypass
Weaknesses CWE-770
References
Metrics cvssV4_0

{'score': 6.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-04T03:11:58.583Z

Reserved: 2026-03-30T16:03:31.047Z

Link: CVE-2026-34516

cve-icon Vulnrichment

Updated: 2026-04-04T03:11:52.806Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-01T21:16:59.723

Modified: 2026-04-15T13:57:47.433

Link: CVE-2026-34516

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-01T20:13:04Z

Links: CVE-2026-34516 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-02T20:16:42Z

Weaknesses