{"api_version":"1","generated_at":"2026-06-26T20:55:35+00:00","cve":"CVE-2026-47778","urls":{"html":"https://cve.report/CVE-2026-47778","api":"https://cve.report/api/cve/CVE-2026-47778.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-47778","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-47778"},"summary":{"title":"Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)","description":"Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .c_str() before being passed to the Utility::dnsNameMatch() algorithm. If the attacker serves a certificate with a dNSName SAN containing an embedded NUL byte, the helper Utility::generalNameAsString captures the complete string including the NUL. However, when .c_str() evaluates it, implicit conversion to absl::string_view inside dnsNameMatch relies on strlen(), prematurely truncating the evaluation context. Envoy evaluates trucated string against the exact required config_san match and returns true, thereby successfully validating the string with the Nul byte for an upstream routing. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-06-26 18:16:59","updated_at":"2026-06-26 19:50:17"},"problem_types":["CWE-158","CWE-158 CWE-158: Improper Neutralization of Null Byte or NUL Character"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"4.4","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N","baseScore":4.4,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"4.4","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.4,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"HIGH","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-f8x4-rw5x-f3r7","name":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-f8x4-rw5x-f3r7","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-47778","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47778","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"envoyproxy","product":"envoy","version":"affected >= 1.38.0, < 1.38.1","platforms":[]},{"source":"CNA","vendor":"envoyproxy","product":"envoy","version":"affected >= 1.37.0, < 1.37.3","platforms":[]},{"source":"CNA","vendor":"envoyproxy","product":"envoy","version":"affected >= 1.36.0, < 1.36.7","platforms":[]},{"source":"CNA","vendor":"envoyproxy","product":"envoy","version":"affected < 1.35.11","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"envoy","vendor":"envoyproxy","versions":[{"status":"affected","version":">= 1.38.0, < 1.38.1"},{"status":"affected","version":">= 1.37.0, < 1.37.3"},{"status":"affected","version":">= 1.36.0, < 1.36.7"},{"status":"affected","version":"< 1.35.11"}]}],"descriptions":[{"lang":"en","value":"Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .c_str() before being passed to the Utility::dnsNameMatch() algorithm. If the attacker serves a certificate with a dNSName SAN containing an embedded NUL byte, the helper Utility::generalNameAsString captures the complete string including the NUL. However, when .c_str() evaluates it, implicit conversion to absl::string_view inside dnsNameMatch relies on strlen(), prematurely truncating the evaluation context. Envoy evaluates trucated string against the exact required config_san match and returns true, thereby successfully validating the string with the Nul byte for an upstream routing. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.4,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"HIGH","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-158","description":"CWE-158: Improper Neutralization of Null Byte or NUL Character","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-06-26T17:27:57.707Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-f8x4-rw5x-f3r7","tags":["x_refsource_CONFIRM"],"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-f8x4-rw5x-f3r7"}],"source":{"advisory":"GHSA-f8x4-rw5x-f3r7","discovery":"UNKNOWN"},"title":"Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS Certificate Validator. (Auth Bypass)"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-47778","datePublished":"2026-06-26T17:27:57.707Z","dateReserved":"2026-05-19T22:36:16.883Z","dateUpdated":"2026-06-26T17:27:57.707Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-26 18:16:59","lastModifiedDate":"2026-06-26 19:50:17","problem_types":["CWE-158","CWE-158 CWE-158: Improper Neutralization of Null Byte or NUL Character"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N","baseScore":4.4,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":0.7,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"47778","Ordinal":"1","Title":"Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS","CVE":"CVE-2026-47778","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"47778","Ordinal":"1","NoteData":"Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a structural flaw was identified in DefaultCertValidator::verifySubjectAltName where the extracted DNS SAN string is cast to a C-style string using .c_str() before being passed to the Utility::dnsNameMatch() algorithm. If the attacker serves a certificate with a dNSName SAN containing an embedded NUL byte, the helper Utility::generalNameAsString captures the complete string including the NUL. However, when .c_str() evaluates it, implicit conversion to absl::string_view inside dnsNameMatch relies on strlen(), prematurely truncating the evaluation context. Envoy evaluates trucated string against the exact required config_san match and returns true, thereby successfully validating the string with the Nul byte for an upstream routing. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.","Type":"Description","Title":"Envoy: Embedded NUL in TLS DNS SAN Truncation in the Default TLS"}]}}}