{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2023-4421", "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "state": "PUBLISHED", "assignerShortName": "mozilla", "dateReserved": "2023-08-18T13:25:38.056Z", "datePublished": "2023-12-12T17:02:08.801Z", "dateUpdated": "2025-11-04T19:25:18.220Z"}, "containers": {"cna": {"affected": [{"product": "NSS", "vendor": "Mozilla", "versions": [{"lessThan": "3.61", "status": "affected", "version": "unspecified", "versionType": "custom"}]}], "descriptions": [{"lang": "en", "value": "The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61."}]}], "problemTypes": [{"descriptions": [{"description": "Timing side-channel in PKCS#1 v1.5 decryption depadding code", "lang": "en", "type": "text"}]}], "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1651411"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2023-53/"}], "credits": [{"lang": "en", "value": "Hubert Kario"}], "providerMetadata": {"orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "shortName": "mozilla", "dateUpdated": "2023-12-12T17:02:08.801Z"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1651411", "tags": ["x_transferred"]}, {"url": "https://www.mozilla.org/security/advisories/mfsa2023-53/", "tags": ["x_transferred"]}, {"url": "https://lists.debian.org/debian-lts-announce/2023/10/msg00039.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-04T19:25:18.220Z"}}]}}

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{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mozilla:nss:*:*:*:*:*:*:*:*", "matchCriteriaId": "885547E8-A55A-4B53-A0A6-FDA8745A5D0D", "versionEndExcluding": "3.6.1", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61."}, {"lang": "es", "value": "El c\u00f3digo NSS utilizado para comprobar PKCS#1 v1.5 estaba filtrando informaci\u00f3n \u00fatil para montar ataques tipo Bleichenbacher. Tanto la exactitud general del relleno como la longitud del mensaje cifrado se filtraban a trav\u00e9s del canal lateral de sincronizaci\u00f3n. Al enviar una gran cantidad de textos cifrados seleccionados por el atacante, el atacante podr\u00eda descifrar un texto cifrado PKCS#1 v1.5 previamente interceptado (por ejemplo, para descifrar una sesi\u00f3n TLS que utiliz\u00f3 el intercambio de claves RSA) o falsificar una firma utilizando el c\u00f3digo de la v\u00edctima. llave. El problema se solucion\u00f3 implementando el algoritmo de rechazo impl\u00edcito, en el que NSS devuelve un mensaje aleatorio determinista en caso de que se detecte un relleno no v\u00e1lido, como se propone en el art\u00edculo de Marvin Attack. Esta vulnerabilidad afecta a NSS &lt; 3.61."}], "id": "CVE-2023-4421", "lastModified": "2025-11-04T20:17:10.927", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2023-12-12T17:15:08.347", "references": [{"source": "security@mozilla.org", "tags": ["Issue Tracking"], "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1651411"}, {"source": "security@mozilla.org", "tags": ["Issue Tracking", "Vendor Advisory"], "url": "https://www.mozilla.org/security/advisories/mfsa2023-53/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Issue Tracking"], "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1651411"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2023/10/msg00039.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Issue Tracking", "Vendor Advisory"], "url": "https://www.mozilla.org/security/advisories/mfsa2023-53/"}], "sourceIdentifier": "security@mozilla.org", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-203"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"acknowledgement": "This issue was discovered by Hubert Kario (Red Hat).", "bugzilla": {"description": "nss: new tlsfuzzer code can still detect timing issues in RSA operations", "id": "2238677", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2238677"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N", "status": "draft"}, "cwe": "CWE-208", "details": ["The NSS code used for checking PKCS#1 v1.5 was leaking information useful in mounting Bleichenbacher-like attacks. Both the overall correctness of the padding as well as the length of the encrypted message was leaking through timing side-channel. By sending large number of attacker-selected ciphertexts, the attacker would be able to decrypt a previously intercepted PKCS#1 v1.5 ciphertext (for example, to decrypt a TLS session that used RSA key exchange), or forge a signature using the victim's key. The issue was fixed by implementing the implicit rejection algorithm, in which the NSS returns a deterministic random message in case invalid padding is detected, as proposed in the Marvin Attack paper. This vulnerability affects NSS < 3.61.", "A vulnerability was found in NSS. The interface between the cryptographic library (the softokn) and the rest of NSS is using PKCS#11, and the error reporting (erroring out when the PKCS#1 v1.5 padding checks fail) that PKCS#11 requires is very noisy, making it easy to detect over the network."], "name": "CVE-2023-4421", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "nss", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "nss", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "nss", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "nss", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2023-09-13T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2023-4421\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-4421"], "threat_severity": "Moderate"}

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