Is CVE-2025-66220 actively exploited?

CVE-2025-66220 has no public evidence of in-the-wild exploitation as of 2025-12-05.

What is the CVSS score for CVE-2025-66220?

CVE-2025-66220 has a CVSS score of 5 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N.

How do I patch CVE-2025-66220?

Patch guidance is available from envoyproxy security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2025-66220.

CVE-2025-66220 - remediation guidance & executive summary

Q: Which products are affected by CVE-2025-66220?

4 products: envoyproxy envoy, envoyproxy envoy, envoyproxy envoy, envoyproxy envoy.

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.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N
Attack Vector: network
Complexity: high
Privileges: high
User Action: none
Scope: unchanged
Confidentiality: high
Integrity: low
Availability: none
Weaknesses: CWE-170

Metadata

Primary Vendor: ENVOYPROXY
Published: 12/3/2025
Last Modified: 12/5/2025
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

envoyproxy : envoyenvoyproxy : envoyenvoyproxy : envoyenvoyproxy : envoy

Remediation Guidance

Executive Summary

Cite this page

CVE-2025-66220. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2025-66220

View on NIST NVD

CVE-2025-66220 vulnerability