{
  "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-2026-93990 Expat through 2.8.4 Malformed UTF-16 Acceptance via Unchecked Surrogate - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-93990.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": "Expat through 2.8.4 Malformed UTF-16 Acceptance via Unchecked Surrogate",
    "tracking": {
      "current_release_date": "2026-10-16T01:45:40.000Z",
      "generator": {
        "date": "2026-10-21T20:21:55.311Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-93990",
      "initial_release_date": "2026-09-21T01:01:24.000Z",
      "revision_history": [
        {
          "date": "2026-09-21T01:01:24.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-09-21T14:51:09.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        },
        {
          "date": "2026-09-25T02:18:22.000Z",
          "legacy_version": "3",
          "number": "3",
          "summary": "Information published."
        },
        {
          "date": "2026-10-01T01:09:55.000Z",
          "legacy_version": "4",
          "number": "4",
          "summary": "Information published."
        },
        {
          "date": "2026-10-05T14:49:27.000Z",
          "legacy_version": "5",
          "number": "5",
          "summary": "Information published."
        },
        {
          "date": "2026-10-07T01:52:02.000Z",
          "legacy_version": "6",
          "number": "6",
          "summary": "Information published."
        },
        {
          "date": "2026-10-16T01:45:40.000Z",
          "legacy_version": "7",
          "number": "7",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "7"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "<azl3 expat 0:2.8.3-2.azl3",
                "product": {
                  "name": "<azl3 expat 0:2.8.3-2.azl3",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "azl3 expat 0:2.8.3-2.azl3",
                "product": {
                  "name": "azl3 expat 0:2.8.3-2.azl3",
                  "product_id": "21887"
                }
              }
            ],
            "category": "product_name",
            "name": "expat"
          },
          {
            "category": "product_name",
            "name": "azl3 cmake 0:3.30.3-15.azl3",
            "product": {
              "name": "azl3 cmake 0:3.30.3-15.azl3",
              "product_id": "3"
            }
          },
          {
            "category": "product_name",
            "name": "azl3 python3 0:3.12.14-2.azl3",
            "product": {
              "name": "azl3 python3 0:3.12.14-2.azl3",
              "product_id": "1"
            }
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 cmake 0:3.30.3-15.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-3"
        },
        "product_reference": "3",
        "relates_to_product_reference": "17084"
      },
      {
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        "full_product_name": {
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        "relates_to_product_reference": "17084"
      },
      {
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        "full_product_name": {
          "name": "<azl3 expat 0:2.8.3-2.azl3 as a component of Azure Linux 3.0",
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        },
        "product_reference": "2",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 expat 0:2.8.3-2.azl3 as a component of Azure Linux 3.0",
          "product_id": "21887-17084"
        },
        "product_reference": "21887",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-93990",
      "cwe": {
        "id": "CWE-176",
        "name": "Improper Handling of Unicode Encoding"
      },
      "notes": [
        {
          "category": "general",
          "text": "VulnCheck",
          "title": "Assigning CNA"
        }
      ],
      "flags": [
        {
          "label": "component_not_present",
          "product_ids": [
            "17084-3",
            "17084-1"
          ]
        }
      ],
      "product_status": {
        "fixed": [
          "21887-17084"
        ],
        "known_affected": [
          "17084-2"
        ],
        "known_not_affected": [
          "17084-3",
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-93990 Expat through 2.8.4 Malformed UTF-16 Acceptance via Unchecked Surrogate - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-93990.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-09-21T01:01:24.000Z",
          "details": "0:2.8.5-1.azl3:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17084-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "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:H/A:N",
            "version": "3.1"
          },
          "products": [
            "17084-2"
          ]
        }
      ],
      "title": "Expat through 2.8.4 Malformed UTF-16 Acceptance via Unchecked Surrogate"
    }
  ]
}