Bug 2418661 (CVE-2025-66220)

Summary: CVE-2025-66220 envoy: Envoy: mTLS certificate validation bypass via embedded null byte in SAN
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Envoy. This vulnerability allows mTLS (mutual Transport Layer Security) certificate validation bypass via a certificate containing an embedded null byte (\0) inside an OTHERNAME SAN (Subject Alternative Name) value.
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Description OSIDB Bzimport 2025-12-03 19:01:55 UTC
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.