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CVE-2026-128124 AIOHTTP: Event loop stall in add_domain() wildcard matching

8.2 high

High (8.2) in aio-libs aiohttp.

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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.

Severity

CVSS 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
CWE
CWE-1333 Inefficient Regular Expression Complexity
Published
Modified
Assigned by
GitHub_M (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
aio-libs aiohttp< 3.14.4

Attack patterns (CAPEC)

  • CAPEC-492 Regular Expression Exponential Blowup

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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