OCSP responder certificate validity period not checked in public_key_CVE-2026-42791

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-05-27T12:23:13.584Z",
    "modified": "2026-05-27T12:23:13.584Z",
    "type": "cve",
    "title": "OCSP responder certificate validity period not checked in public_key",
    "source": "EEF",
    "references": "https://github.com/erlang/otp/security/advisories/GHSA-cjxj-wj6x-3fff\nhttps://cna.erlef.org/cves/CVE-2026-42791.html\nhttps://osv.dev/vulnerability/EEF-CVE-2026-42791\nhttps://www.erlang.org/doc/system/versions.html#order-of-versions\nhttps://github.com/erlang/otp/commit/7995f1fdaee3da569bb810358ce0f546471d169b\nhttps://github.com/erlang/otp/commit/b3870e02405c709a872b01ba6086065620cdfe76",
    "id": "CVE-2026-42791",
    "bulletinFamily": "",
    "cwe": [
        "CWE-295",
        "CWE-672"
    ],
    "cvelist": null,
    "sourceData": "Erlang OTP 1.16\nErlang OTP 27.0\nErlang OTP 2b1a742c651b90f8a7a1fb2ddde73f29915ea376",
    "sourceHref": "",
    "cvss": {
        "score": 6.3,
        "severity": "MEDIUM",
        "vector": "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"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "OTP",
    "version": "1.16",
    "vendor": "Erlang",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}