{
  "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-2021-22926 libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`) a malicious user can create a file name with the same name as the app wants to use by name and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-22926.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": "libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`) a malicious user can create a file name with the same name as the app wants to use by name and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.",
    "tracking": {
      "current_release_date": "2021-12-16T00:00:00.000Z",
      "generator": {
        "date": "2025-10-19T22:09:27.537Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2021-22926",
      "initial_release_date": "2021-08-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2021-08-17T00:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2021-12-16T00:00:00.000Z",
          "legacy_version": "1.1",
          "number": "2",
          "summary": "Added curl to CBL-Mariner 2.0"
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "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 curl 7.76.0-7",
                "product": {
                  "name": "\u003ccm1 curl 7.76.0-7",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "cm1 curl 7.76.0-7",
                "product": {
                  "name": "cm1 curl 7.76.0-7",
                  "product_id": "19010"
                }
              },
              {
                "category": "product_version_range",
                "name": "\u003ccbl2 curl 7.82.0-1",
                "product": {
                  "name": "\u003ccbl2 curl 7.82.0-1",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "cbl2 curl 7.82.0-1",
                "product": {
                  "name": "cbl2 curl 7.82.0-1",
                  "product_id": "18989"
                }
              }
            ],
            "category": "product_name",
            "name": "curl"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccm1 curl 7.76.0-7 as a component of CBL Mariner 1.0",
          "product_id": "16820-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cm1 curl 7.76.0-7 as a component of CBL Mariner 1.0",
          "product_id": "19010-16820"
        },
        "product_reference": "19010",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccbl2 curl 7.82.0-1 as a component of CBL Mariner 2.0",
          "product_id": "17086-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 curl 7.82.0-1 as a component of CBL Mariner 2.0",
          "product_id": "18989-17086"
        },
        "product_reference": "18989",
        "relates_to_product_reference": "17086"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-22926",
      "cwe": {
        "id": "CWE-295",
        "name": "Improper Certificate Validation"
      },
      "notes": [
        {
          "category": "general",
          "text": "hackerone",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "19010-16820",
          "18989-17086"
        ],
        "known_affected": [
          "16820-1",
          "17086-2"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-22926 libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`) a malicious user can create a file name with the same name as the app wants to use by name and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-22926.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2021-08-17T00:00:00.000Z",
          "details": "7.76.0-7:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "16820-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        },
        {
          "category": "vendor_fix",
          "date": "2021-08-17T00:00:00.000Z",
          "details": "7.82.0-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17086-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "environmentalsScore": 0.0,
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "temporalScore": 7.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "16820-1",
            "17086-2"
          ]
        }
      ],
      "title": "libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`) a malicious user can create a file name with the same name as the app wants to use by name and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake."
    }
  ]
}