CVE-2021-40528 (GCVE-0-2021-40528)
Vulnerability from cvelistv5
Published
2021-09-06 00:00
Modified
2025-06-09 15:13
Severity ?
5.9 (Medium) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
  • n/a
Summary
The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.
References
Impacted products
Vendor Product Version
n/a n/a Version: n/a
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T02:44:10.845Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://eprint.iacr.org/2021/923"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320"
          },
          {
            "name": "GLSA-202210-13",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202210-13"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "HIGH",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 5.9,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-40528",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-06-09T15:12:20.359985Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-327",
                "description": "CWE-327 Use of a Broken or Risky Cryptographic Algorithm",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-06-09T15:13:03.906Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver\u0027s public key, the generator defined by the receiver\u0027s public key, and the sender\u0027s ephemeral exponents can lead to a cross-configuration attack against OpenPGP."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2022-10-31T00:00:00.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://eprint.iacr.org/2021/923"
        },
        {
          "url": "https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1"
        },
        {
          "url": "https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2"
        },
        {
          "url": "https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320"
        },
        {
          "name": "GLSA-202210-13",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.gentoo.org/glsa/202210-13"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2021-40528",
    "datePublished": "2021-09-06T00:00:00.000Z",
    "dateReserved": "2021-09-06T00:00:00.000Z",
    "dateUpdated": "2025-06-09T15:13:03.906Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-40528\",\"sourceIdentifier\":\"cve@mitre.org\",\"published\":\"2021-09-06T19:15:07.587\",\"lastModified\":\"2025-06-09T16:15:33.000\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver\u0027s public key, the generator defined by the receiver\u0027s public key, and the sender\u0027s ephemeral exponents can lead to a cross-configuration attack against OpenPGP.\"},{\"lang\":\"es\",\"value\":\"Una implementaci\u00f3n de ElGamal en Libgcrypt versiones anteriores a 1.9.4, permite una recuperaci\u00f3n de texto plano porque, durante la interacci\u00f3n entre dos bibliotecas criptogr\u00e1ficas, una determinada combinaci\u00f3n peligrosa del primo definido por la clave p\u00fablica del receptor, el generador definido por la clave p\u00fablica del receptor y los exponentes ef\u00edmeros del emisor puede conllevar a un ataque de configuraci\u00f3n cruzada contra OpenPGP.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N\",\"baseScore\":5.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":3.6},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N\",\"baseScore\":5.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":3.6}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:N/AC:H/Au:N/C:P/I:N/A:N\",\"baseScore\":2.6,\"accessVector\":\"NETWORK\",\"accessComplexity\":\"HIGH\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"PARTIAL\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"baseSeverity\":\"LOW\",\"exploitabilityScore\":4.9,\"impactScore\":2.9,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":false}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-327\"}]},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-327\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:gnupg:libgcrypt:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.9.4\",\"matchCriteriaId\":\"E8F745E7-4B6F-404D-997D-0B27ED8DB2D6\"}]}]}],\"references\":[{\"url\":\"https://eprint.iacr.org/2021/923\",\"source\":\"cve@mitre.org\",\"tags\":[\"Technical Description\",\"Third Party Advisory\"]},{\"url\":\"https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1\",\"source\":\"cve@mitre.org\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2\",\"source\":\"cve@mitre.org\",\"tags\":[\"Exploit\",\"Third Party Advisory\"]},{\"url\":\"https://security.gentoo.org/glsa/202210-13\",\"source\":\"cve@mitre.org\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://eprint.iacr.org/2021/923\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Technical Description\",\"Third Party Advisory\"]},{\"url\":\"https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Third Party Advisory\"]},{\"url\":\"https://security.gentoo.org/glsa/202210-13\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://eprint.iacr.org/2021/923\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://security.gentoo.org/glsa/202210-13\", \"name\": \"GLSA-202210-13\", \"tags\": [\"vendor-advisory\", \"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T02:44:10.845Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.9, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-40528\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-06-09T15:12:20.359985Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-327\", \"description\": \"CWE-327 Use of a Broken or Risky Cryptographic Algorithm\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-06-09T15:12:40.237Z\"}}], \"cna\": {\"affected\": [{\"vendor\": \"n/a\", \"product\": \"n/a\", \"versions\": [{\"status\": \"affected\", \"version\": \"n/a\"}]}], \"references\": [{\"url\": \"https://eprint.iacr.org/2021/923\"}, {\"url\": \"https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1\"}, {\"url\": \"https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2\"}, {\"url\": \"https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320\"}, {\"url\": \"https://security.gentoo.org/glsa/202210-13\", \"name\": \"GLSA-202210-13\", \"tags\": [\"vendor-advisory\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver\u0027s public key, the generator defined by the receiver\u0027s public key, and the sender\u0027s ephemeral exponents can lead to a cross-configuration attack against OpenPGP.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"text\", \"description\": \"n/a\"}]}], \"providerMetadata\": {\"orgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"shortName\": \"mitre\", \"dateUpdated\": \"2022-10-31T00:00:00.000Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-40528\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-06-09T15:13:03.906Z\", \"dateReserved\": \"2021-09-06T00:00:00.000Z\", \"assignerOrgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"datePublished\": \"2021-09-06T00:00:00.000Z\", \"assignerShortName\": \"mitre\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.