{
  "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\u0027s 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."
    },
    {
      "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 \u0026lt; 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"
    }
  ]
}