# CVE-2025-66220

## Summary

- **CVE ID:** CVE-2025-66220
- **Severity:** MEDIUM
- **CVSS Score:** 5 (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N)
- **CWE:** CWE-170
- **Published:** Dec 3, 2025
- **Last Modified:** Mar 13, 2026

## 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.

## Affected Products

- envoyproxy — envoy (>= 1.36.0, <= 1.36.2)
- envoyproxy — envoy (>= 1.35.0, <= 1.35.6)
- envoyproxy — envoy (>= 1.34.0, <= 1.34.10)
- envoyproxy — envoy (<= 1.33.12)

## References

- [CNA](https://github.com/envoyproxy/envoy/security/advisories/GHSA-rwjg-c3h2-f57p)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.17%
- **EPSS Percentile:** 6.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._