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.

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required High

Scope Unchanged

Confidentiality Impact High

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00002.

Exploitation poc

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
envoyproxy envoy affected
Version Status Constraints
>= 1.36.0, <= 1.36.2 affected —
>= 1.35.0, <= 1.35.6 affected —
>= 1.34.0, <= 1.34.10 affected —
<= 1.33.12 affected —

Configuration 1 [-]

OR cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*

No data.

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Vendors Products
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Envoy Subscribe

Project Subscriptions

Vendors Products
Envoyproxy Subscribe
Envoy Subscribe
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-rwjg-c3h2-f57p Envoy's TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/envoyproxy/envoy/security/advisories/GHSA-rwjg-c3h2-f57p cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-66220 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-66220 cve-icon
History

Wed, 17 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 threat_severity

Moderate

Fri, 05 Dec 2025 15:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*

Thu, 04 Dec 2025 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Envoyproxy
Envoyproxy envoy
Vendors & Products Envoyproxy
Envoyproxy envoy

Wed, 03 Dec 2025 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 03 Dec 2025 19:00:00 +0000

Type Values Removed Values Added
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.
Title Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte
Weaknesses CWE-170
References
Metrics cvssV3_1

{'score': 5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-12-03T19:10:53.694Z

Reserved: 2025-11-24T23:01:29.679Z

Link: CVE-2025-66220

cve-icon Vulnrichment

Updated: 2025-12-03T19:10:49.222Z

cve-icon NVD

Status : Analyzed

Published: 2025-12-03T19:15:58.010

Modified: 2025-12-05T15:44:26.663

Link: CVE-2025-66220

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-03T18:31:50Z

Links: CVE-2025-66220 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-12-04T16:43:54Z

Weaknesses