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{
  "affected": [],
  "aliases": [
    "CVE-2026-45991"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:16Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nudf: fix partition descriptor append bookkeeping\n\nMounting a crafted UDF image with repeated partition descriptors can\ntrigger a heap out-of-bounds write in part_descs_loc[].\n\nhandle_partition_descriptor() deduplicates entries by partition number,\nbut appended slots never record partnum. As a result duplicate\nPartition Descriptors are appended repeatedly and num_part_descs keeps\ngrowing.\n\nOnce the table is full, the growth path still sizes the allocation from\npartnum even though inserts are indexed by num_part_descs. If partnum is\nalready aligned to PART_DESC_ALLOC_STEP, ALIGN(partnum, step) can keep\nthe old capacity and the next append writes past the end of the table.\n\nStore partnum in the appended slot and size growth from the next append\ncount so deduplication and capacity tracking follow the same model.",
  "id": "GHSA-x889-prf3-g3vg",
  "modified": "2026-06-19T15:33:11Z",
  "published": "2026-05-27T15:33:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45991"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/058b451b1039f056d1362c4fec2229e522366ab0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08841b06fa64d8edbd1a21ca6e613420c90cc4b8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08fa5d818e5bf53c7ca234d88ba334f32004e9b6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68013a9bd4c01acd42073715f00e1a1992f089ee"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad3c0c4400686f6f37b382aaa48fac2b9aefccbe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b5597bb83fc37b5b5da74a4453fa920b932cf39a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e8474cfbac9ada2cdaa4eaedec22aadfa0f58559"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

{
  "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-2026-45991 udf: fix partition descriptor append bookkeeping - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-45991.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": "udf: fix partition descriptor append bookkeeping",
    "tracking": {
      "current_release_date": "2026-06-09T14:50:46.000Z",
      "generator": {
        "date": "2026-06-10T07:16:12.142Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-45991",
      "initial_release_date": "2026-05-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-05-28T01:04:53.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-05-28T14:47:36.000Z",
          "legacy_version": "1.1",
          "number": "2",
          "summary": "Information published."
        },
        {
          "date": "2026-05-29T01:43:48.000Z",
          "legacy_version": "2",
          "number": "3",
          "summary": "Information published."
        },
        {
          "date": "2026-06-09T14:50:46.000Z",
          "legacy_version": "3",
          "number": "4",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "4"
    }
  },
  "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": "\u003cazl3 kernel 0:6.6.139.1-1.azl3",
                "product": {
                  "name": "\u003cazl3 kernel 0:6.6.139.1-1.azl3",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "azl3 kernel 0:6.6.139.1-1.azl3",
                "product": {
                  "name": "azl3 kernel 0:6.6.139.1-1.azl3",
                  "product_id": "21344"
                }
              }
            ],
            "category": "product_name",
            "name": "kernel"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003cazl3 kernel 0:6.6.139.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 kernel 0:6.6.139.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "21344-17084"
        },
        "product_reference": "21344",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-45991",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "21344-17084"
        ],
        "known_affected": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-45991 udf: fix partition descriptor append bookkeeping - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-45991.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-05-28T01:04:53.000Z",
          "details": "0:6.6.141.1-1.azl3:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17084-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "title": "udf: fix partition descriptor append bookkeeping"
    }
  ]
}