CVE-2025-66220

Name: CVE-2025-66220
Creator: NVD / NIST
Published: 2025-12-03T19:15:58.01+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.1/10EPSS 0.16%

Last modified Jun 17, 2026

CVE-2025-66220 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. 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.. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.1/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

EPSS Probability

0.16%

5.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-170

Affected Software

Vendor	Product	Versions
Envoyproxy	Envoy	< 1.33.13
Envoyproxy	Envoy	>= 1.34.0, < 1.34.11
Envoyproxy	Envoy	>= 1.35.0, < 1.35.7
Envoyproxy	Envoy	>= 1.36.0, < 1.36.3

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-rwjg-c3h2-f57pExploit, Vendor Advisory

Timeline

Published: Dec 3, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-66220?

How severe is CVE-2025-66220?

CVE-2025-66220 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2025-66220?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-66220?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST