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.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-82r6-8w77-94w6 | AnyIO: TLSStream IDNA 2003 host name encoding enables potential TLS certificate spoofing |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 22 Sep 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Agronholm
Agronholm anyio |
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| Vendors & Products |
Agronholm
Agronholm anyio |
Tue, 22 Sep 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | AnyIO: TLSStream IDNA 2003 host name encoding enables potential TLS certificate spoofing | |
| Weaknesses | CWE-295 CWE-297 |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-09-22T15:23:14.259Z
Reserved: 2026-07-16T17:39:30.170Z
Link: CVE-2026-63374
No data.
Status : Received
Published: 2026-09-22T16:17:50.680
Modified: 2026-09-22T16:17:50.680
Link: CVE-2026-63374
No data.
OpenCVE Enrichment
Updated: 2026-09-22T16:30:11Z
Github GHSA