CVE-2026-63374
AnyIO: TLSStream IDNA 2003 host name encoding enables potential TLS certificate spoofing
Reported by github_m · Published September 22, 2026
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.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| airflow-core-2 | Chainguard | 2.11.2-r8 |
| wazuh-manager | Chainguard | 4.14.7-r4 |
| litellm | Chainguard | 1.101.0-r2 |
| kserve | Chainguard | 0.20.0-r9 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| agronholm | anyio | < 4.14.2 |
| chainguard | airflow-core-2 | 0 |
| chainguard | wazuh-manager | 0 |
| chainguard | litellm | 0 |
| chainguard | kserve | 0 |
| Cloudflare | stream | |
| agronholm | anyio | 0 |
| chainguard | py3.14-anyio | 0 |
| chainguard | kserve-huggingfaceserver-cuda-13.3 | 0 |
| wolfi | kserve | 0 |
| chainguard | localstack | 0 |
| chainguard | open-webui | 0 |
| AWS | connect | |
| chainguard | authentik-2026.5 | 0 |
| PyPI | anyio | 0 |
| SAP | concur | |
| chainguard | wazuh-manager-fips | 0 |
| chainguard | airflow-2 | 0 |
| chainguard | authentik-fips-2026.5 | 0 |
| wolfi | open-webui | 0 |
…and 1 more
Timeline
- Sep 18, 2026 CVE Published
- Sep 23, 2026 EPSS Score (14 in total, the first dated here)
- Sep 28, 2026 CVE Updated
- Oct 2, 2026 Security Advisory
Query this with the API
The same record, from the CLI:
vulnetix vdb vuln CVE-2026-63374
vulnetix vdb fixes CVE-2026-63374Or with curl, using the org id and key from your account page:
curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
"https://api.vdb.vulnetix.com/v2/vuln/CVE-2026-63374/fixes/registry"The Community plan is free and allows 50 queries a day. Get a free API key · API quickstart
References
- https://github.com/agronholm/anyio/security/advisories/GHSA-82r6-8w77-94w6 x_refsource_CONFIRM
- https://github.com/agronholm/anyio/pull/1208 x_refsource_MISC
- https://github.com/agronholm/anyio/commit/68f58915f82d9be8109ebbbd8f5d70577d43f2ce x_refsource_MISC
- https://github.com/agronholm/anyio/releases/tag/4.14.2 x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-63374 advisory
- https://github.com/advisories/GHSA-82r6-8w77-94w6 advisory