CVE-2026-128124
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: not scored yet.
- Severity: 8.2 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Weakness
- CWE-1333
- Record status
- Awaiting Analysis
Attack profile CVSS 4.0 · 8.2
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-128124.md and follow it. Check whether this project is affected by CVE-2026-128124. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/aio-libs/aiohttp/commit/766b882820da0651c84090e366a3b024b4a263c9
- https://github.com/aio-libs/aiohttp/commit/c6ac0e44c3c573ff9616f4a6a532992538b31e43
- https://github.com/aio-libs/aiohttp/pull/13943
- https://github.com/aio-libs/aiohttp/pull/13945
- https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jm3w-gw2p-xjfj
References
- https://github.com/aio-libs/aiohttp/commit/766b882820da0651c84090e366a3b024b4a263c9
- https://github.com/aio-libs/aiohttp/commit/c6ac0e44c3c573ff9616f4a6a532992538b31e43
- https://github.com/aio-libs/aiohttp/pull/13943
- https://github.com/aio-libs/aiohttp/pull/13945
- https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jm3w-gw2p-xjfj