Vulnerability Description
AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. Prior to 4.14.2, connect_tcp() and TLSStream.wrap() can validate internationalized host names after the standard library converts them with IDNA 2003 instead of IDNA 2008. When a connection to a non-ASCII domain is hijacked or redirected, an attacker can obtain a legitimate certificate for the different ASCII hostname produced by IDNA 2003 and present it to the client, causing the malicious endpoint's certificate to validate. This issue is fixed in version 4.14.2.
Related Weaknesses (CWE)
References
- https://github.com/agronholm/anyio/commit/68f58915f82d9be8109ebbbd8f5d70577d43f2
- https://github.com/agronholm/anyio/pull/1208
- https://github.com/agronholm/anyio/releases/tag/4.14.2
- https://github.com/agronholm/anyio/security/advisories/GHSA-82r6-8w77-94w6
FAQ
What is CVE-2026-63374?
CVE-2026-63374 is a documented vulnerability. AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. Prior to 4.14.2, connect_tcp() and TLSStream.wrap() can validate internationalized ...
How severe is CVE-2026-63374?
CVSS scoring is not yet available for CVE-2026-63374. Check NVD for updates.
Is there a patch for CVE-2026-63374?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.