{"id":"CVE-2023-4421","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 \u003c 3.61.","modified":"2026-03-13T07:44:49.807112Z","published":"2023-12-12T17:15:08.347Z","references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00039.html"},{"type":"REPORT","url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1651411"},{"type":"REPORT","url":"https://www.mozilla.org/security/advisories/mfsa2023-53/"}],"affected":[{"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"0"},{"fixed":"3.6.1"}]}],"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-4421.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"}]}