CVE-2025-66220
Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte
5.0
MEDIUM
CVSS 3.1
EPSS 0.00%
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.
How to fix CVE-2025-66220
To remediate CVE-2025-66220, upgrade the affected package to a fixed version below.
- —upgrade to 1.33.13 or later
- —upgrade to 1.36.3 or later
Is CVE-2025-66220 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 1.33.13, >= 1.34.0, < 1.34.11, >= 1.35.0, < 1.35.7, >= 1.36.0, < 1.36.3
- >= 1.36.0, < 1.36.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.0 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N |