{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-64431",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64431",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-07-25T08:51:07.194Z",
    "updatedAt": "2026-08-17T04:55:32.047Z",
    "importedAt": "2026-10-24T01:58:25.636Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "ntfs: avoid calling post_write_mst_fixup() for invalid index_block",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: avoid calling post_write_mst_fixup() for invalid index_block\n\nntfs_icx_ib_sync_write() calls post_write_mst_fixup() when ntfs_ib_write()\nreturns an error, intending to restore the buffer after a failed write.\n\nHowever, ntfs_ib_write() returns an error immediately if\npre_write_mst_fixup() validation fails. The caller,\nntfs_icx_ib_sync_write(), interprets any error as a write failure\nrequiring rollback. It does not differentiate between I/O errors and\nvalidation failures, and calls post_write_mst_fixup() anyway.\n\nSince post_write_mst_fixup() assumes that the index_block contents is\ncorrect, it doesn't perform the boundary checks, which results in\nout-of-bounds memory access.\n\nAn attacker can craft a malicious NTFS image with:\n  - large index_block.usa_ofs offset, pointing outside the ntfs_record\n  - index_block.usa_count = 0, causing integer underflow\n  - or index_block.usa_count larger than actual number of sectors in the\n    ntfs_record, causing out-of-bounds access\n\nKASAN reports describing the memory corruption:\n  ==================================================================\n  BUG: KASAN: slab-out-of-bounds in post_write_mst_fixup+0x19c/0x1d0\n  Read of size 2 at addr ffff8881586c9018 by task p/9428\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x100/0x190\n   print_report+0x139/0x4ad\n   ? post_write_mst_fixup+0x19c/0x1d0\n   ? __virt_addr_valid+0x262/0x500\n   ? post_write_mst_fixup+0x19c/0x1d0\n   kasan_report+0xe4/0x1d0\n   ? post_write_mst_fixup+0x19c/0x1d0\n   post_write_mst_fixup+0x19c/0x1d0\n   ntfs_icx_ib_sync_write+0x179/0x220\n   ntfs_inode_sync_filename+0x83d/0x1080\n   __ntfs_write_inode+0x1049/0x1480\n   ntfs_file_fsync+0x131/0x9b0\n  ==================================================================\n  BUG: KASAN: slab-out-of-bounds in post_write_mst_fixup+0x1aa/0x1d0\n  Write of size 2 at addr ffff8881586c91fe by task p/9428\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x100/0x190\n   print_report+0x139/0x4ad\n   ? post_write_mst_fixup+0x1aa/0x1d0\n   ? __virt_addr_valid+0x262/0x500\n   ? post_write_mst_fixup+0x1aa/0x1d0\n   kasan_report+0xe4/0x1d0\n   ? post_write_mst_fixup+0x1aa/0x1d0\n   post_write_mst_fixup+0x1aa/0x1d0\n   ntfs_icx_ib_sync_write+0x179/0x220\n   ntfs_inode_sync_filename+0x83d/0x1080\n   __ntfs_write_inode+0x1049/0x1480\n   ntfs_file_fsync+0x131/0x9b0\n  ==================================================================\n\nLet's move the post_write_mst_fixup() call to ntfs_ib_write().\nThe ntfs_ib_write() function calls pre_write_mst_fixup() at the beginning.\nIf the index_block contents is invalid, pre_write_mst_fixup() fails and\nntfs_ib_write() returns early without calling post_write_mst_fixup() on\nbad index_block.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e2018628301a6d9f54e34b0cb417f1688c66df1d"
            },
            {
              "version": "0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0",
              "status": "affected",
              "versionType": "git",
              "lessThan": "5b6eedd7cc2936f9238e852b553a1b326105bde8"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "7.1",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "7.1"
            },
            {
              "version": "7.1.4",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "version": "7.2",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}