CVE-2026-63374
NVD: AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. NVD: 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. NVD: 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.
9.3 Severity
CRITICAL EPSS
0.0029 (19) KEV
-
Source-published summary
NVD: AnyIO is a high level asynchronous concurrency and networking framework that works on top of either Trio or asyncio. NVD: 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. NVD: 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.
Possible impact
This critical severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for critical severity review.
Affected context
Affected product or version requires source confirmation.
Remediation / advisory
Patch confirmed by source text; fixed version context: 4.14.2..
Why it matters
This critical severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for critical severity review.; CVSS 9.3 (CRITICAL); EPSS percentile 19; not listed in KEV; Patch confirmed by source text; fixed version context: 4.14.2; sources: NVD, OSV.
What to verify
Confirm affected product/version, vendor advisory, patch or mitigation, and exposure.
Exposure hint
exposure unknown
Impact tags
Urgency reasons
Source-derived note
Summary derived from NVD / OSV description; unsafe procedural detail is not shown.
Redaction metadata
- source summary used
- True
- fallback summary used
- False
- unsafe procedural detail present
- false
- raw source displayed
- false
- public summary redacted
- true
Remediation handoff
Public-safe static handoff for human/Codex remediation planning. Scan, patch, external execution, and auto remediation are disabled.
Safety note
This radar shows source-published defensive context only. Exploit procedures, exploit strings, scanner commands, and auto-remediation are not provided.