{"cve":"CVE-2026-90131","nvd":{"published":"2026-09-17T17:17:05.617","modified":"2026-10-19T09:19:02.813","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: serialize resident iomap reads with mrec_lock\n\nntfs_read_iomap_begin_resident() walks the MFT record through\nntfs_attr_lookup() -> ntfs_attr_find() without taking ni->mrec_lock,\nwhile ntfs_attr_record_resize(), ntfs_make_room_for_attr() and\nntfs_resident_attr_record_add() memmove() the same base_ni->mrec buffer\nunder that lock. map_mft_record() only takes a reference and does not\nserialize, so the reader can observe torn attribute length and offset\nfields while a writer is relocating the records.\n\nKCSAN reports the race between the mmap read fault path and both link()\nand unlink():\n\n  BUG: KCSAN: data-race in ntfs_attr_find / ntfs_attr_record_resize\n\n  write to 0xffff888100af1018 of 4 bytes by task 96 on cpu 1:\n   ntfs_attr_record_resize+0xd2/0x130\n   ntfs_attr_record_rm+0xad/0x530\n   ntfs_delete+0x224/0x640\n   ntfs_unlink+0x14d/0x280\n   vfs_unlink+0x157/0x520\n\n  read to 0xffff888100af1018 of 4 bytes by task 95 on cpu 0:\n   ntfs_attr_find+0x104/0x5b0\n   ntfs_attr_lookup+0x39c/0x10c0\n   ntfs_read_iomap_begin_resident+0xc6/0x230\n   ntfs_read_iomap_begin+0x5d/0xa0\n   iomap_iter+0x2e2/0x6e0\n   iomap_read_folio+0x147/0x2a0\n   ntfs_read_folio+0x108/0x170\n   filemap_read_folio+0x35/0x100\n   filemap_fault+0x993/0x1000\n\n  value changed: 0x00000250 -> 0x000001f0\n\nThe address is mrec + 0x18, i.e. mft_record.bytes_in_use, and the change\nis the 96 bytes of one $FILE_NAME attribute being removed.\n\nKeep base_ni->mrec_lock from the resident read iomap lookup through\niomap_end(). This protects both the attribute walk and the subsequent copy\nfrom iomap->inline_data, which points into the MFT record. The non-resident\npath is left alone: ntfs_lookup() already holds the directory inode's\nmrec_lock when it reads an index folio through read_mapping_folio(), and\ntaking the lock in the shared wrapper deadlocks there with recursive locking\non mrec_lock. The comment above the read_mapping_folio() call in\nfs/ntfs/dir.c notes the same hazard.\n\nThe seek path uses the same lookup helper but does not dereference\niomap->inline_data. Release the lock before returning from that path,\nwhereas the regular read path records base_ni in iomap->private and releases\nthe lock from its iomap_end() callback.\n\nTested with a reproducer that faults in a 16-byte resident file while\nanother thread runs link()/unlink() on it. Before: 40 KCSAN reports in\nabout one second. After: no reports in 180 seconds over 206,090 read\niterations and 423,540 link/unlink cycles. A PROVE_LOCKING build shows no\nlockdep splat with the same reproducer running for 60 seconds.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","score":7.1},"cwes":[],"references":["https://git.kernel.org/stable/c/0400e0d50eb3be19c98323faa322b652e4ae3f99","https://git.kernel.org/stable/c/d9e00c457d4ab8ab59c6e4b8554c921260e4e16c"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-90131","score":0.00156,"percentile":0.04723,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}