{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2021-3521 There is a flaw in RPM\u0027s signature functionality. OpenPGP subkeys are associated with a primary key via a \"binding signature.\" RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2022/msrc_cve-2021-3521.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "There is a flaw in RPM\u0027s signature functionality. OpenPGP subkeys are associated with a primary key via a \"binding signature.\" RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources.",
    "tracking": {
      "current_release_date": "2022-08-27T00:00:00.000Z",
      "generator": {
        "date": "2025-10-19T23:51:07.193Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2021-3521",
      "initial_release_date": "2022-08-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2022-08-27T00:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "1.0",
                "product": {
                  "name": "CBL Mariner 1.0",
                  "product_id": "16820"
                }
              },
              {
                "category": "product_version",
                "name": "2.0",
                "product": {
                  "name": "CBL Mariner 2.0",
                  "product_id": "17086"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003ccm1 rpm 4.14.2-15",
                "product": {
                  "name": "\u003ccm1 rpm 4.14.2-15",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "cm1 rpm 4.14.2-15",
                "product": {
                  "name": "cm1 rpm 4.14.2-15",
                  "product_id": "18858"
                }
              },
              {
                "category": "product_version_range",
                "name": "\u003ccbl2 rpm 4.18.0-1",
                "product": {
                  "name": "\u003ccbl2 rpm 4.18.0-1",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "cbl2 rpm 4.18.0-1",
                "product": {
                  "name": "cbl2 rpm 4.18.0-1",
                  "product_id": "18859"
                }
              }
            ],
            "category": "product_name",
            "name": "rpm"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccm1 rpm 4.14.2-15 as a component of CBL Mariner 1.0",
          "product_id": "16820-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cm1 rpm 4.14.2-15 as a component of CBL Mariner 1.0",
          "product_id": "18858-16820"
        },
        "product_reference": "18858",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccbl2 rpm 4.18.0-1 as a component of CBL Mariner 2.0",
          "product_id": "17086-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 rpm 4.18.0-1 as a component of CBL Mariner 2.0",
          "product_id": "18859-17086"
        },
        "product_reference": "18859",
        "relates_to_product_reference": "17086"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-3521",
      "cwe": {
        "id": "CWE-347",
        "name": "Improper Verification of Cryptographic Signature"
      },
      "notes": [
        {
          "category": "general",
          "text": "redhat",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "18858-16820",
          "18859-17086"
        ],
        "known_affected": [
          "16820-2",
          "17086-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-3521 There is a flaw in RPM\u0027s signature functionality. OpenPGP subkeys are associated with a primary key via a \"binding signature.\" RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2022/msrc_cve-2021-3521.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2022-08-27T00:00:00.000Z",
          "details": "4.14.2-15:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "16820-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        },
        {
          "category": "vendor_fix",
          "date": "2022-08-27T00:00:00.000Z",
          "details": "4.18.0-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17086-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 4.7,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "environmentalsScore": 0.0,
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "temporalScore": 4.7,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
          "products": [
            "16820-2",
            "17086-1"
          ]
        }
      ],
      "title": "There is a flaw in RPM\u0027s signature functionality. OpenPGP subkeys are associated with a primary key via a \"binding signature.\" RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. To exploit this flaw an attacker must either compromise an RPM repository or convince an administrator to install an untrusted RPM or public key. It is strongly recommended to only use RPMs and public keys from trusted sources."
    }
  ]
}