{"id":"CVE-2026-90117","summary":"ntfs: validate usa_ofs before preserving the update sequence number","details":"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-\u003eusa_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-\u003eusa_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 -\u003e __ntfs_create -\u003e ntfs_create -\u003e 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.","modified":"2026-09-19T03:47:28.464218983Z","published":"2026-09-17T16:06:22.705Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90117.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/81684340963da2e898eabb8c1e274433d9375bc6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ea5a3c30710710c1dc5e483d3313309ec2e868f7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90117.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90117"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"495e90fa334828d4119061e2726af51d0a0fb4ed"},{"fixed":"ea5a3c30710710c1dc5e483d3313309ec2e868f7"},{"fixed":"81684340963da2e898eabb8c1e274433d9375bc6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90117.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.1.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90117.json"}}],"schema_version":"1.9.0"}