CVE-2026-42791 (GCVE-0-2026-42791)
Vulnerability from cvelistv5 – Published: 2026-05-27 12:23 – Updated: 2026-07-24 14:14
VLAI
EPSS
VEX
Title
OCSP responder certificate validity period not checked in public_key
Summary
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.
OCSP 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.
This 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 — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate.
This issue affects OTP from OTP 27.0 before OTP 29.0.1, OTP 28.5.0.1 and OTP 27.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-27 15:40 UTC
CWE
Assigner
References
6 references
| URL | Tags |
|---|---|
| https://github.com/erlang/otp/security/advisories… | vendor-advisoryrelated |
| https://cna.erlef.org/cves/CVE-2026-42791.html | related |
| https://osv.dev/vulnerability/EEF-CVE-2026-42791 | related |
| https://www.erlang.org/doc/system/versions.html#o… | x_version-scheme |
| https://github.com/erlang/otp/commit/7995f1fdaee3… | patch |
| https://github.com/erlang/otp/commit/b3870e02405c… | patch |
Impacted products
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-42791",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-27T15:40:27.647844Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-05-27T15:40:49.123Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"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\u0026vcs_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 \u003ctt\u003essl\u003c/tt\u003e application, OCSP stapling must be enabled by setting the \u003ctt\u003estapling\u003c/tt\u003e option to \u003ctt\u003estaple\u003c/tt\u003e in the TLS client options. OCSP stapling is not enabled by default.\u003cp\u003eApplications calling \u003ctt\u003epublic_key:pkix_ocsp_validate/5\u003c/tt\u003e directly are unconditionally affected when that function is used.\u003c/p\u003e"
}
],
"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 Anderton Andin"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Improper Certificate Validation vulnerability in Erlang OTP \u003ctt\u003epublic_key\u003c/tt\u003e (\u003ctt\u003epubkey_ocsp\u003c/tt\u003e module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.\u003cp\u003eOCSP response verification in \u003ctt\u003epubkey_ocsp:verify_response/5\u003c/tt\u003e and \u003ctt\u003epubkey_ocsp:is_authorized_responder/3\u003c/tt\u003e in \u003ctt\u003elib/public_key/src/pubkey_ocsp.erl\u003c/tt\u003e does not check the validity period (\u003ctt\u003enotBefore\u003c/tt\u003e/\u003ctt\u003enotAfter\u003c/tt\u003e) 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.\u003c/p\u003e\u003cp\u003eThis affects TLS clients using OCSP stapling via the \u003ctt\u003essl\u003c/tt\u003e 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 \u003ctt\u003epublic_key:pkix_ocsp_validate/5\u003c/tt\u003e 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.\u003c/p\u003e\u003cp\u003eThis issue affects OTP from OTP 27.0 before OTP\u0026nbsp;29.0.1, OTP\u0026nbsp;28.5.0.1 and OTP\u0026nbsp;27.3.4.12, corresponding to \u003ctt\u003epublic_key\u003c/tt\u003e from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3.\u003c/p\u003e"
}
],
"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\u00a029.0.1, OTP\u00a028.5.0.1 and OTP\u00a027.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3."
}
],
"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": {
"dateUpdated": "2026-07-24T14:14:24.911Z",
"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"shortName": "EEF"
},
"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": "\u003cul\u003e\u003cli\u003eFor TLS clients using the \u003ctt\u003essl\u003c/tt\u003e application, disable OCSP stapling by setting \u003ctt\u003e{stapling, no_staple}\u003c/tt\u003e in the client options, or switch to CRL-based revocation checking with \u003ctt\u003e{crl_check, true}\u003c/tt\u003e.\u003c/li\u003e\u003cli\u003eFor applications calling \u003ctt\u003epublic_key:pkix_ocsp_validate/5\u003c/tt\u003e directly, validate the responder certificate\u0027s validity period in application code before calling the function.\u003c/li\u003e\u003c/ul\u003e"
}
],
"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\u0027s validity period in application code before calling the function."
}
],
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"assignerShortName": "EEF",
"cveId": "CVE-2026-42791",
"datePublished": "2026-05-27T12:23:13.584Z",
"dateReserved": "2026-04-29T18:06:33.251Z",
"dateUpdated": "2026-07-24T14:14:24.911Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-42791",
"date": "2026-09-29",
"epss": "0.00321",
"percentile": "0.22675"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"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\u0026vcs_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"
}
]
}
],
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
"matchCriteriaId": "91269F6D-B8A3-41F2-871C-79EBB9460BE8",
"versionEndExcluding": "27.3.4.12",
"versionStartIncluding": "27.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
"matchCriteriaId": "844A3F01-AF3C-4C48-81DB-932B803D22C4",
"versionEndExcluding": "28.5.0.1",
"versionStartIncluding": "28.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
"matchCriteriaId": "46976598-817C-4E93-AC4B-46434746C25F",
"versionEndExcluding": "29.0.1",
"versionStartIncluding": "29.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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\u00a029.0.1, OTP\u00a028.5.0.1 and OTP\u00a027.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3."
}
],
"id": "CVE-2026-42791",
"lastModified": "2026-07-24T15:17:18.703",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 3.7,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.2,
"impactScore": 1.4,
"source": "nvd@nist.gov",
"type": "Primary"
}
],
"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"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-42791",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-27T15:40:27.647844Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-05-27T14:16:53.460",
"references": [
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"tags": [
"Third Party Advisory"
],
"url": "https://cna.erlef.org/cves/CVE-2026-42791.html"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"tags": [
"Patch"
],
"url": "https://github.com/erlang/otp/commit/7995f1fdaee3da569bb810358ce0f546471d169b"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"tags": [
"Patch"
],
"url": "https://github.com/erlang/otp/commit/b3870e02405c709a872b01ba6086065620cdfe76"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"tags": [
"Mitigation",
"Vendor Advisory"
],
"url": "https://github.com/erlang/otp/security/advisories/GHSA-cjxj-wj6x-3fff"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"tags": [
"Third Party Advisory"
],
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-42791"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"tags": [
"Product"
],
"url": "https://www.erlang.org/doc/system/versions.html#order-of-versions"
}
],
"sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-295"
},
{
"lang": "en",
"value": "CWE-672"
}
],
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-09-21T11:53:49+00:00",
"cve": "CVE-2026-42791",
"id": "CVE-2026-42791",
"initial_release_date": "2026-05-27T12:23:13.584000+00:00",
"product_status:fixed": "79",
"product_status:known_not_affected": "42",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "erlang: Erlang OTP: Authentication bypass due to improper OCSP certificate validation",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42791.json",
"version": "3"
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-42791",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-27T15:40:27.647844Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-05-27T15:40:33.572Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"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\u0026vcs_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 \u003ctt\u003essl\u003c/tt\u003e application, OCSP stapling must be enabled by setting the \u003ctt\u003estapling\u003c/tt\u003e option to \u003ctt\u003estaple\u003c/tt\u003e in the TLS client options. OCSP stapling is not enabled by default.\u003cp\u003eApplications calling \u003ctt\u003epublic_key:pkix_ocsp_validate/5\u003c/tt\u003e directly are unconditionally affected when that function is used.\u003c/p\u003e"
}
],
"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 Anderton Andin"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "Improper Certificate Validation vulnerability in Erlang OTP \u003ctt\u003epublic_key\u003c/tt\u003e (\u003ctt\u003epubkey_ocsp\u003c/tt\u003e module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.\u003cp\u003eOCSP response verification in \u003ctt\u003epubkey_ocsp:verify_response/5\u003c/tt\u003e and \u003ctt\u003epubkey_ocsp:is_authorized_responder/3\u003c/tt\u003e in \u003ctt\u003elib/public_key/src/pubkey_ocsp.erl\u003c/tt\u003e does not check the validity period (\u003ctt\u003enotBefore\u003c/tt\u003e/\u003ctt\u003enotAfter\u003c/tt\u003e) 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.\u003c/p\u003e\u003cp\u003eThis affects TLS clients using OCSP stapling via the \u003ctt\u003essl\u003c/tt\u003e 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 \u003ctt\u003epublic_key:pkix_ocsp_validate/5\u003c/tt\u003e 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.\u003c/p\u003e\u003cp\u003eThis issue affects OTP from OTP 27.0 before OTP\u0026nbsp;29.0.1, OTP\u0026nbsp;28.5.0.1 and OTP\u0026nbsp;27.3.4.12, corresponding to \u003ctt\u003epublic_key\u003c/tt\u003e from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3.\u003c/p\u003e"
}
],
"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\u00a029.0.1, OTP\u00a028.5.0.1 and OTP\u00a027.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3."
}
],
"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": {
"dateUpdated": "2026-07-24T14:14:24.911Z",
"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"shortName": "EEF"
},
"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": "\u003cul\u003e\u003cli\u003eFor TLS clients using the \u003ctt\u003essl\u003c/tt\u003e application, disable OCSP stapling by setting \u003ctt\u003e{stapling, no_staple}\u003c/tt\u003e in the client options, or switch to CRL-based revocation checking with \u003ctt\u003e{crl_check, true}\u003c/tt\u003e.\u003c/li\u003e\u003cli\u003eFor applications calling \u003ctt\u003epublic_key:pkix_ocsp_validate/5\u003c/tt\u003e directly, validate the responder certificate\u0027s validity period in application code before calling the function.\u003c/li\u003e\u003c/ul\u003e"
}
],
"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\u0027s validity period in application code before calling the function."
}
],
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"assignerShortName": "EEF",
"cveId": "CVE-2026-42791",
"datePublished": "2026-05-27T12:23:13.584Z",
"dateReserved": "2026-04-29T18:06:33.251Z",
"dateUpdated": "2026-07-24T14:14:24.911Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…