{"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"}}]}}