CVE-2025-66220

Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte

State: Published
Severity: 5.0 Medium
Published: Dec 3, 2025
Updated: Dec 3, 2025
Reserved: Nov 24, 2025

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Description

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, Envoy’s mTLS certificate matcher for match_typed_subject_alt_names may incorrectly treat certificates containing an embedded null byte (\0) inside an OTHERNAME SAN value as valid matches.

Scores

CVSS	Score	Vector	Source
3.1	5.0 Medium	CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N	GitHub_M

Weaknesses

CWE-170 Improper Null Termination

Affected Products

Product	Versions
envoyenvoyproxy	>= 1.36.0, <= 1.36.2Affected >= 1.35.0, <= 1.35.6Affected >= 1.34.0, <= 1.34.10Affected <= 1.33.12Affected

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-rwjg-c3h2-f57p

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