{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-42791", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-04-29T18:06:33.251Z", "datePublished": "2026-05-27T12:23:13.584Z", "dateUpdated": "2026-05-27T12:23:13.584Z"}, "containers": {"cna": {"affected": [{"cpes": ["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"], "defaultStatus": "unknown", "modules": ["pubkey_ocsp"], "packageName": "public_key", "packageURL": "pkg:otp/public_key?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp&vcs_url=git%20https:%2F%2Fgithub.com%2Ferlang%2Fotp.git", "product": "OTP", "programFiles": ["src/pubkey_ocsp.erl"], "programRoutines": [{"name": "pubkey_ocsp:verify_response/5"}, {"name": "pubkey_ocsp:is_authorized_responder/3"}], "repo": "https://github.com/erlang/otp", "vendor": "Erlang", "versions": [{"changes": [{"at": "1.17.1.3", "status": "unaffected"}, {"at": "1.20.3.1", "status": "unaffected"}, {"at": "1.21.1", "status": "unaffected"}], "lessThan": "*", "status": "affected", "version": "1.16", "versionType": "otp"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"], "defaultStatus": "unknown", "modules": ["pubkey_ocsp"], "packageName": "erlang/otp", "packageURL": "pkg:github/erlang/otp", "product": "OTP", "programFiles": ["lib/public_key/src/pubkey_ocsp.erl"], "programRoutines": [{"name": "pubkey_ocsp:verify_response/5"}, {"name": "pubkey_ocsp:is_authorized_responder/3"}], "repo": "https://github.com/erlang/otp", "vendor": "Erlang", "versions": [{"changes": [{"at": "27.3.4.12", "status": "unaffected"}, {"at": "28.5.0.1", "status": "unaffected"}, {"at": "29.0.1", "status": "unaffected"}], "lessThan": "*", "status": "affected", "version": "27.0", "versionType": "otp"}, {"changes": [{"at": "7995f1fdaee3da569bb810358ce0f546471d169b", "status": "unaffected"}, {"at": "b3870e02405c709a872b01ba6086065620cdfe76", "status": "unaffected"}], "lessThan": "*", "status": "affected", "version": "2b1a742c651b90f8a7a1fb2ddde73f29915ea376", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "For the <tt>ssl</tt> application, OCSP stapling must be enabled by setting the <tt>stapling</tt> option to <tt>staple</tt> in the TLS client options. OCSP stapling is not enabled by default.<p>Applications calling <tt>public_key:pkix_ocsp_validate/5</tt> directly are unconditionally affected when that function is used.</p>"}], "value": "For the ssl application, OCSP stapling must be enabled by setting the stapling option to staple in the TLS client options. OCSP stapling is not enabled by default.\n\nApplications calling public_key:pkix_ocsp_validate/5 directly are unconditionally affected when that function is used."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*", "versionEndExcluding": "27.3.4.12", "versionStartIncluding": "27.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*", "versionEndExcluding": "28.5.0.1", "versionStartIncluding": "28.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*", "versionEndExcluding": "29.0.1", "versionStartIncluding": "29.0", "vulnerable": true}], "negate": false, "operator": "OR"}], "operator": "AND"}], "credits": [{"lang": "en", "type": "remediation developer", "value": "Jakub Witczak"}, {"lang": "en", "type": "remediation reviewer", "value": "Ingela Andin"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Improper Certificate Validation vulnerability in Erlang OTP <tt>public_key</tt> (<tt>pubkey_ocsp</tt> module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.<p>OCSP response verification in <tt>pubkey_ocsp:verify_response/5</tt> and <tt>pubkey_ocsp:is_authorized_responder/3</tt> in <tt>lib/public_key/src/pubkey_ocsp.erl</tt> does not check the validity period (<tt>notBefore</tt>/<tt>notAfter</tt>) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid.</p><p>This affects TLS clients using OCSP stapling via the <tt>ssl</tt> application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling <tt>public_key:pkix_ocsp_validate/5</tt> directly, where the impact depends on the use case \u2014 server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate.</p><p>This issue affects OTP from OTP 27.0 before OTP 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to <tt>public_key</tt> from 1.16 before 1.17.1.3, 1.20.3.1, and 1.21.1.</p>"}], "value": "Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.\n\nOCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid.\n\nThis affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case \u2014 server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate.\n\nThis issue affects OTP from OTP 27.0 before OTP 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.16 before 1.17.1.3, 1.20.3.1, and 1.21.1."}], "impacts": [{"capecId": "CAPEC-475", "descriptions": [{"lang": "en", "value": "CAPEC-475 Signature Spoofing by Improper Validation"}]}], "metrics": [{"cvssV4_0": {"attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "baseScore": 6.3, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "NONE", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-295", "description": "CWE-295 Improper Certificate Validation", "lang": "en", "type": "CWE"}, {"cweId": "CWE-672", "description": "CWE-672 Operation on a Resource after Expiration or Release", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-05-27T12:23:13.584Z"}, "references": [{"tags": ["vendor-advisory", "related"], "url": "https://github.com/erlang/otp/security/advisories/GHSA-cjxj-wj6x-3fff"}, {"tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-42791.html"}, {"tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-42791"}, {"tags": ["x_version-scheme"], "url": "https://www.erlang.org/doc/system/versions.html#order-of-versions"}, {"tags": ["patch"], "url": "https://github.com/erlang/otp/commit/7995f1fdaee3da569bb810358ce0f546471d169b"}, {"tags": ["patch"], "url": "https://github.com/erlang/otp/commit/b3870e02405c709a872b01ba6086065620cdfe76"}], "source": {"discovery": "INTERNAL"}, "title": "OCSP responder certificate validity period not checked in public_key", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<ul><li>For TLS clients using the <tt>ssl</tt> application, disable OCSP stapling by setting <tt>{stapling, no_staple}</tt> in the client options, or switch to CRL-based revocation checking with <tt>{crl_check, true}</tt>.</li><li>For applications calling <tt>public_key:pkix_ocsp_validate/5</tt> directly, validate the responder certificate's validity period in application code before calling the function.</li></ul>"}], "value": "* For TLS clients using the ssl application, disable OCSP stapling by setting {stapling, no_staple} in the client options, or switch to CRL-based revocation checking with {crl_check, true}.\n* For applications calling public_key:pkix_ocsp_validate/5 directly, validate the responder certificate's validity period in application code before calling the function."}], "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.\n\nOCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid.\n\nThis affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case \u2014 server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate.\n\nThis issue affects OTP from OTP 27.0 before OTP 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.16 before 1.17.1.3, 1.20.3.1, and 1.21.1."}], "id": "CVE-2026-42791", "lastModified": "2026-05-27T14:16:53.460", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}, "published": "2026-05-27T14:16:53.460", "references": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://cna.erlef.org/cves/CVE-2026-42791.html"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/erlang/otp/commit/7995f1fdaee3da569bb810358ce0f546471d169b"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/erlang/otp/commit/b3870e02405c709a872b01ba6086065620cdfe76"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/erlang/otp/security/advisories/GHSA-cjxj-wj6x-3fff"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://osv.dev/vulnerability/EEF-CVE-2026-42791"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://www.erlang.org/doc/system/versions.html#order-of-versions"}], "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-295"}, {"lang": "en", "value": "CWE-672"}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}

{}

{}