{"id":"CVE-2026-89612","state":"PUBLISHED","title":"ntfs: reject invalid MFT LCNs from boot sector","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: reject invalid MFT LCNs from boot sector\n\nThe NTFS boot sector stores the MFT and MFTMirr locations as unsigned\n64-bit LCNs, but parse_ntfs_boot_sector() decoded them into an s64.\n\nA crafted high-bit value could therefore become negative and pass\nthe existing upper-bound check. The invalid value then propagated into\nthe MFT zone allocator and could result in an out-of-bounds access to\nlcn_empty_bits_per_page.","publishedAt":"2026-09-11T19:45:13.415Z","updatedAt":"2026-10-19T08:49:44.526Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"11ccc9107dc460de28af90fac1f42404d9802735","status":"affected","lessThan":"8f8420b68a6f05ca2b03779d8208814ec539b9e5","versionType":"git"},{"version":"11ccc9107dc460de28af90fac1f42404d9802735","status":"affected","lessThan":"cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/super.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/super.c"]}],"references":["https://git.kernel.org/stable/c/8f8420b68a6f05ca2b03779d8208814ec539b9e5","https://git.kernel.org/stable/c/cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89612.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89612","state":"PUBLISHED","datePublished":"2026-09-11T19:45:13.415Z","dateUpdated":"2026-10-19T08:49:44.526Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.734Z"},"containers":{"cna":{"title":"ntfs: reject invalid MFT LCNs from boot sector","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: reject invalid MFT LCNs from boot sector\n\nThe NTFS boot sector stores the MFT and MFTMirr locations as unsigned\n64-bit LCNs, but parse_ntfs_boot_sector() decoded them into an s64.\n\nA crafted high-bit value could therefore become negative and pass\nthe existing upper-bound check. The invalid value then propagated into\nthe MFT zone allocator and could result in an out-of-bounds access to\nlcn_empty_bits_per_page."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"11ccc9107dc460de28af90fac1f42404d9802735","status":"affected","lessThan":"8f8420b68a6f05ca2b03779d8208814ec539b9e5","versionType":"git"},{"version":"11ccc9107dc460de28af90fac1f42404d9802735","status":"affected","lessThan":"cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/super.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.4","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/super.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8f8420b68a6f05ca2b03779d8208814ec539b9e5"},{"url":"https://git.kernel.org/stable/c/cc9d09fef78410bcd37ac05168cbd5f6dd75d3d2"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - After a crafted NTFS volume is mounted, fs/ntfs registers ntfs_export_ops, so nfsd/ksmbd VFS writes and creates reach ntfs_cluster_alloc() and index the poisoned MFT-zone LCN into lcn_empty_bits_per_page without local shell access.\nAC:L - The attacker fully controls the unsigned 64-bit MFT/MFTMirr LCNs in the boot sector; a high-bit value becomes a negative s64, bypasses the signed upper-bound check, and later allocator walks use that value as bmp_pos with no race or rare config.\nPR:N - Triggering the allocator needs only write access to a mounted NTFS export (guest/anonymous SMB or a permissive NFS export) or an unprivileged write on an already-mounted volume, not init-namespace root or CAP_SYS_ADMIN at trigger time.\nUI:N - After the crafted volume is mounted and exported, ordinary remote or local write/create operations invoke ntfs_cluster_alloc() with the poisoned mft_zone_pos; no extra victim mount dialog or USB insertion is required during the attack.\nS:U - Out-of-bounds access to vol->lcn_empty_bits_per_page corrupts kernel heap within the host OS security domain and does not cross a VM, container, or IOMMU boundary to another authority.\nC:H - ntfs_cluster_alloc() reads lcn_empty_bits_per_page[index] where index is derived from the attacker-chosen negative LCN (truncating to a controllable pgoff_t on 32-bit), an unbounded kernel heap out-of-bounds read that can disclose adjacent objects.\nI:H - The same attacker-influenced index is passed to ntfs_set_lcn_empty_bits(), which increments or decrements lcn_empty_bits_per_page[index], a kernel heap out-of-bounds write exploitable for arbitrary write and control-flow hijacking.\nA:H - The out-of-bounds lcn_empty_bits_per_page index causes a kernel oops or KASAN slab-out-of-bounds fault in ntfs_cluster_alloc()/ntfs_set_lcn_empty_bits(), crashing or hanging the host even when not fully exploited."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:49:44.526Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}