# CVE-2026-63374: python-anyio: AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio

CVE-2026-63374 is fixed in python-anyio on 1 platform, first by SUSE-SU-2026:4416-1, released October 2, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-63374
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0029
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 22, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-anyio Debian 14 | 4.15.1-1 | [DEBIAN-CVE-2026-63374](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63374.md) | Oct 6, 2026 |
| Linux | python-anyio opensuse-leap 16.0 | 4.8.0-160000.3.1 | [OPENSUSE-SU-2026:22060-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22060-1.md) | Nov 7, 2026 |
| Linux | python-anyio sles 15.6 | 4.1.0-150400.9.11.1 | [SUSE-SU-2026:4416-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4416-1.md) | Oct 2, 2026 |
| Linux | python-anyio sles 15.7 | 4.1.0-150400.9.11.1 | [SUSE-SU-2026:4416-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4416-1.md) | Oct 2, 2026 |
| Linux | python-anyio sles 16.0 | 4.8.0-160000.3.1 | [SUSE-SU-2026:24208-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24208-1.md) | Nov 7, 2026 |

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Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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