{"id":"CVE-2026-90117","state":"PUBLISHED","title":"ntfs: validate usa_ofs before preserving the update sequence number","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: validate usa_ofs before preserving the update sequence number\n\nWhen ntfs_mft_record_alloc() reuses a free mft record it reads the old\nupdate sequence number straight from the on-disk record:\n\n     usn = *(__le16 *)((u8 *)m + le16_to_cpu(m->usa_ofs));\n\nHere m points into the raw $MFT page-cache folio, which still holds\nunvalidated, MST-protected bytes: the folio is read by a plain\niomap_read_folio() and neither post_read_mst_fixup() nor\nntfs_mft_record_check() has run on it (both work on private copies).\nm->usa_ofs is therefore an untrusted u16, and a corrupted record can put\nit past the end of the record so the two-byte read lands outside the\nfolio.  Reading such a record while creating a file gives, under KASAN:\n\n   BUG: KASAN: use-after-free in ntfs_mft_record_alloc+...\n   Read of size 2 at addr ...\n    ntfs_mft_record_alloc -> __ntfs_create -> ntfs_create -> path_openat\n\nOnly preserve the old update sequence number when usa_ofs is even and in\nrange, mirroring the check ntfs_mft_record_check() already applies;\notherwise leave usn zero, which the existing restore below skips.","publishedAt":"2026-09-17T16:06:22.705Z","updatedAt":"2026-10-19T08:58:15.750Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"495e90fa334828d4119061e2726af51d0a0fb4ed","status":"affected","lessThan":"ea5a3c30710710c1dc5e483d3313309ec2e868f7","versionType":"git"},{"version":"495e90fa334828d4119061e2726af51d0a0fb4ed","status":"affected","lessThan":"81684340963da2e898eabb8c1e274433d9375bc6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/mft.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.6","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/mft.c"]}],"references":["https://git.kernel.org/stable/c/ea5a3c30710710c1dc5e483d3313309ec2e868f7","https://git.kernel.org/stable/c/81684340963da2e898eabb8c1e274433d9375bc6"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90117.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90117","state":"PUBLISHED","datePublished":"2026-09-17T16:06:22.705Z","dateUpdated":"2026-10-19T08:58:15.750Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.787Z"},"containers":{"cna":{"title":"ntfs: validate usa_ofs before preserving the update sequence number","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: validate usa_ofs before preserving the update sequence number\n\nWhen ntfs_mft_record_alloc() reuses a free mft record it reads the old\nupdate sequence number straight from the on-disk record:\n\n     usn = *(__le16 *)((u8 *)m + le16_to_cpu(m->usa_ofs));\n\nHere m points into the raw $MFT page-cache folio, which still holds\nunvalidated, MST-protected bytes: the folio is read by a plain\niomap_read_folio() and neither post_read_mst_fixup() nor\nntfs_mft_record_check() has run on it (both work on private copies).\nm->usa_ofs is therefore an untrusted u16, and a corrupted record can put\nit past the end of the record so the two-byte read lands outside the\nfolio.  Reading such a record while creating a file gives, under KASAN:\n\n   BUG: KASAN: use-after-free in ntfs_mft_record_alloc+...\n   Read of size 2 at addr ...\n    ntfs_mft_record_alloc -> __ntfs_create -> ntfs_create -> path_openat\n\nOnly preserve the old update sequence number when usa_ofs is even and in\nrange, mirroring the check ntfs_mft_record_check() already applies;\notherwise leave usn zero, which the existing restore below skips."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"495e90fa334828d4119061e2726af51d0a0fb4ed","status":"affected","lessThan":"ea5a3c30710710c1dc5e483d3313309ec2e868f7","versionType":"git"},{"version":"495e90fa334828d4119061e2726af51d0a0fb4ed","status":"affected","lessThan":"81684340963da2e898eabb8c1e274433d9375bc6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ntfs/mft.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"7.2.6","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/mft.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ea5a3c30710710c1dc5e483d3313309ec2e868f7"},{"url":"https://git.kernel.org/stable/c/81684340963da2e898eabb8c1e274433d9375bc6"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:58:15.750Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}