{"api_version":"1","generated_at":"2026-06-26T20:55:32+00:00","cve":"CVE-2026-55964","urls":{"html":"https://cve.report/CVE-2026-55964","api":"https://cve.report/api/cve/CVE-2026-55964.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-55964","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55964"},"summary":{"title":"Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA (temporary CA exemption)","description":"Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA. Intermediate CA certificates are required to have the keyCertSign key usage when a Key Usage extension is present, but chain-supplied temporary CAs (WOLFSSL_TEMP_CA) added while building a certificate path were previously exempted from this check, so an intermediate asserting CA:TRUE but lacking keyCertSign was accepted as a signing CA. The check now applies to chain-supplied temporary CAs as well; only operator-loaded root certificates (WOLFSSL_USER_CA) and self-signed roots remain exempt. Per RFC 5280 an absent Key Usage extension implies all usages, so the requirement is enforced only when the extension is actually present (extKeyUsageSet). Affects the OpenSSL-compatibility certificate-path-building path (X509_verify_cert / X509_STORE, OPENSSL_EXTRA/OPENSSL_ALL), where untrusted chain intermediates are added as temporary CAs; native (non-OpenSSL-compat) certificate verification does not create temporary CAs and is unaffected. Within those builds, the check applies unless ALLOW_INVALID_CERTSIGN is defined.","state":"PUBLISHED","assigner":"wolfSSL","published_at":"2026-06-25 20:17:16","updated_at":"2026-06-26 18:53:47"},"problem_types":["CWE-295","CWE-295 CWE-295 Improper Certificate Validation"],"metrics":[{"version":"4.0","source":"facts@wolfssl.com","type":"Secondary","score":"6.3","severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","data":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":6.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"6.3","severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","data":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnerabilityResponseEffort":"NOT_DEFINED"}},{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"}}],"references":[{"url":"https://github.com/wolfSSL/wolfssl/pull/10702","name":"https://github.com/wolfSSL/wolfssl/pull/10702","refsource":"facts@wolfssl.com","tags":["Issue Tracking","Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.wolfssl.com/docs/security-vulnerabilities/","name":"https://www.wolfssl.com/docs/security-vulnerabilities/","refsource":"facts@wolfssl.com","tags":["Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-55964","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55964","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"wolfSSL","product":"wolfSSL","version":"affected 5.7.4 5.9.1 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"NVIDIA Project Vanessa","lang":"en"}],"nvd_cpes":[{"cve_year":"2026","cve_id":"55964","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"wolfssl","cpe5":"wolfssl","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-55964","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-06-26T13:56:12.832072Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-06-26T13:57:29.942Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"collectionURL":"https://github.com/wolfSSL/wolfssl","defaultStatus":"unaffected","product":"wolfSSL","vendor":"wolfSSL","versions":[{"lessThanOrEqual":"5.9.1","status":"affected","version":"5.7.4","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"NVIDIA Project Vanessa"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA. Intermediate CA certificates are required to have the keyCertSign key usage when a Key Usage extension is present, but chain-supplied temporary CAs (WOLFSSL_TEMP_CA) added while building a certificate path were previously exempted from this check, so an intermediate asserting CA:TRUE but lacking keyCertSign was accepted as a signing CA. The check now applies to chain-supplied temporary CAs as well; only operator-loaded root certificates (WOLFSSL_USER_CA) and self-signed roots remain exempt. Per RFC 5280 an absent Key Usage extension implies all usages, so the requirement is enforced only when the extension is actually present (extKeyUsageSet). Affects the OpenSSL-compatibility certificate-path-building path (X509_verify_cert / X509_STORE, OPENSSL_EXTRA/OPENSSL_ALL), where untrusted chain intermediates are added as temporary CAs; native (non-OpenSSL-compat) certificate verification does not create temporary CAs and is unaffected. Within those builds, the check applies unless ALLOW_INVALID_CERTSIGN is defined.</p>"}],"value":"Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA. Intermediate CA certificates are required to have the keyCertSign key usage when a Key Usage extension is present, but chain-supplied temporary CAs (WOLFSSL_TEMP_CA) added while building a certificate path were previously exempted from this check, so an intermediate asserting CA:TRUE but lacking keyCertSign was accepted as a signing CA. The check now applies to chain-supplied temporary CAs as well; only operator-loaded root certificates (WOLFSSL_USER_CA) and self-signed roots remain exempt. Per RFC 5280 an absent Key Usage extension implies all usages, so the requirement is enforced only when the extension is actually present (extKeyUsageSet). Affects the OpenSSL-compatibility certificate-path-building path (X509_verify_cert / X509_STORE, OPENSSL_EXTRA/OPENSSL_ALL), where untrusted chain intermediates are added as temporary CAs; native (non-OpenSSL-compat) certificate verification does not create temporary CAs and is unaffected. Within those builds, the check applies unless ALLOW_INVALID_CERTSIGN is defined."}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-295","description":"CWE-295 Improper Certificate Validation","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-06-25T19:30:34.789Z","orgId":"50d2cd11-d01a-48ed-9441-5bfce9d63b27","shortName":"wolfSSL"},"references":[{"tags":["patch"],"url":"https://github.com/wolfSSL/wolfssl/pull/10702"},{"url":"https://www.wolfssl.com/docs/security-vulnerabilities/"}],"source":{"discovery":"UNKNOWN"},"title":"Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA (temporary CA exemption)","x_generator":{"engine":"Vulnogram 1.0.2"}}},"cveMetadata":{"assignerOrgId":"50d2cd11-d01a-48ed-9441-5bfce9d63b27","assignerShortName":"wolfSSL","cveId":"CVE-2026-55964","datePublished":"2026-06-25T19:30:34.789Z","dateReserved":"2026-06-17T22:11:03.530Z","dateUpdated":"2026-06-26T13:57:29.942Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-25 20:17:16","lastModifiedDate":"2026-06-26 18:53:47","problem_types":["CWE-295","CWE-295 CWE-295 Improper Certificate Validation"],"metrics":{"cvssMetricV40":[{"source":"facts@wolfssl.com","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":6.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":1.4}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-06-26T13:56:12.832072Z","id":"CVE-2026-55964","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7.4","versionEndExcluding":"5.9.2","matchCriteriaId":"B1EF9B6B-1F1B-485B-8B93-BC02295532E1"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"55964","Ordinal":"1","Title":"Chain intermediate CA:TRUE without keyCertSign accepted as a sig","CVE":"CVE-2026-55964","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"55964","Ordinal":"1","NoteData":"Chain intermediate CA:TRUE without keyCertSign accepted as a signing CA. Intermediate CA certificates are required to have the keyCertSign key usage when a Key Usage extension is present, but chain-supplied temporary CAs (WOLFSSL_TEMP_CA) added while building a certificate path were previously exempted from this check, so an intermediate asserting CA:TRUE but lacking keyCertSign was accepted as a signing CA. The check now applies to chain-supplied temporary CAs as well; only operator-loaded root certificates (WOLFSSL_USER_CA) and self-signed roots remain exempt. Per RFC 5280 an absent Key Usage extension implies all usages, so the requirement is enforced only when the extension is actually present (extKeyUsageSet). Affects the OpenSSL-compatibility certificate-path-building path (X509_verify_cert / X509_STORE, OPENSSL_EXTRA/OPENSSL_ALL), where untrusted chain intermediates are added as temporary CAs; native (non-OpenSSL-compat) certificate verification does not create temporary CAs and is unaffected. Within those builds, the check applies unless ALLOW_INVALID_CERTSIGN is defined.","Type":"Description","Title":"Chain intermediate CA:TRUE without keyCertSign accepted as a sig"}]}}}