AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Application.add_domain() converts every asterisk wildcard in a domain mask into a greedy regular-expression fragment, so a mask containing two or more wildcards can take polynomial time to reject a long Host header that does not match. A remote attacker can repeatedly send such headers to a server configured with a multi-wildcard domain mask and stall the event loop. This issue is fixed in version 3.14.4.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

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.

No EPSS score available.

Key SSVC decision points have not yet been added.

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
< 3.14.4 affected —

No data.

No data.

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Advisories

No advisories yet.

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/766b882820da0651c84090e366a3b024b4a263c9 cve-icon cve-icon
https://github.com/aio-libs/aiohttp/commit/c6ac0e44c3c573ff9616f4a6a532992538b31e43 cve-icon cve-icon
https://github.com/aio-libs/aiohttp/pull/13943 cve-icon cve-icon
https://github.com/aio-libs/aiohttp/pull/13945 cve-icon cve-icon
https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4 cve-icon cve-icon
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jm3w-gw2p-xjfj cve-icon cve-icon
History

Fri, 13 Nov 2026 22:15:00 +0000

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

Fri, 13 Nov 2026 20:30:00 +0000

Type Values Removed Values Added
Description AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, Application.add_domain() converts every asterisk wildcard in a domain mask into a greedy regular-expression fragment, so a mask containing two or more wildcards can take polynomial time to reject a long Host header that does not match. A remote attacker can repeatedly send such headers to a server configured with a multi-wildcard domain mask and stall the event loop. This issue is fixed in version 3.14.4.
Title AIOHTTP: Event loop stall in add_domain() wildcard matching
Weaknesses CWE-1333
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/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: 2026-11-13T20:22:36.733Z

Reserved: 2026-11-12T22:42:47.031Z

Link: CVE-2026-128124

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-13T21:17:44.003

Modified: 2026-11-13T22:11:32.147

Link: CVE-2026-128124

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-13T22:00:09Z

Weaknesses