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CVE-2020-26939

Estado: ModificadaMedia (5.3)—

In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, attackers can obtain sensitive information about a private exponent because of Observable Differences in Behavior to Error Inputs. This occurs in org.bouncycastle.crypto.encodings.OAEPEncoding. Sending invalid ciphertext that decrypts to a short payload in the OAEP Decoder could result in the throwing of an early exception, potentially leaking some information about the private exponent of the RSA private key performing the encryption.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (2)

Bouncycastle — Fips Java APIBouncycastle — Legion-of-the-bouncy-castle

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2020-26939",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-11-02T22:15:13.393",
  "references": [
    {
      "url": "https://github.com/bcgit/bc-java/wiki/CVE-2020-26939",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://lists.apache.org/thread.html/r8c36ba34e80e05eecb1f80071cc834d705616f315b634ec0c7d8f42e%40%3Cissues.solr.apache.org%3E",
      "source": "cve@mitre.org"
    },
    {
      "url": "https://github.com/bcgit/bc-java/wiki/CVE-2020-26939",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.apache.org/thread.html/r8c36ba34e80e05eecb1f80071cc834d705616f315b634ec0c7d8f42e%40%3Cissues.solr.apache.org%3E",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-203"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In Legion of the Bouncy Castle BC before 1.61 and BC-FJA before 1.0.1.2, attackers can obtain sensitive information about a private exponent because of Observable Differences in Behavior to Error Inputs. This occurs in org.bouncycastle.crypto.encodings.OAEPEncoding. Sending invalid ciphertext that decrypts to a short payload in the OAEP Decoder could result in the throwing of an early exception, potentially leaking some information about the private exponent of the RSA private key performing the encryption."
    },
    {
      "lang": "es",
      "value": "En Legion of the Bouncy Castle BC versiones anteriores a 1.61 y BC-FJA versiones anteriores a 1.0.1.2, los atacantes pueden obtener información confidencial sobre un exponente privado debido a las diferencias observables en el comportamiento de las entradas de error. Esto se presenta en org.bouncycastle.crypto.encodings.OAEPEncoding. El envío de texto cifrado no válido que es descifrado en una carga útil corta en el decodificador OAEP podría resultar en el lanzamiento de una excepción temprana, filtrando potencialmente alguna información sobre el exponente privado de la clave privada RSA que realiza el cifrado"
    }
  ],
  "lastModified": "2026-06-17T03:08:35.110",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:bouncycastle:fips_java_api:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F0B7168C-AAB1-4E4D-8B38-C50C38FBF3D6",
              "versionEndExcluding": "1.0.1.2"
            },
            {
              "criteria": "cpe:2.3:a:bouncycastle:legion-of-the-bouncy-castle:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B5ECAFEE-393F-426E-8BF8-752D09EFF9F2",
              "versionEndExcluding": "1.61"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}