CVE-2026-128124
AIOHTTP: Event loop stall in add_domain() wildcard matching
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.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| aiohttp aio-libs |
< 3.14.4 (affected) | CNA: GitHub_M |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.2 high |
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 | CNA: GitHub_M |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jm3w-gw2p-xjfjCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/aio-libs/aiohttp/pull/13943CNA: GitHub_M · x_refsource_MISC
- https://github.com/aio-libs/aiohttp/pull/13945CNA: GitHub_M · x_refsource_MISC
- https://github.com/aio-libs/aiohttp/commit/766b882820da0651c84090e366a3b024b4a263c9CNA: GitHub_M · x_refsource_MISC
- https://github.com/aio-libs/aiohttp/commit/c6ac0e44c3c573ff9616f4a6a532992538b31e43CNA: GitHub_M · x_refsource_MISC
- https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4CNA: GitHub_M · x_refsource_MISC
For agents and automation
Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.
Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.
Endpoints and access details
https://api.y2.dev/api/v2/cyber/cveshttps://api.y2.dev/api/v2/cyber/cves/{cveId}
A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.
For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.