CVE-2026-90131
ntfs: serialize resident iomap reads with mrec_lock
Description
In the Linux kernel, the following vulnerability has been resolved: ntfs: serialize resident iomap reads with mrec_lock ntfs_read_iomap_begin_resident() walks the MFT record through ntfs_attr_lookup() -> ntfs_attr_find() without taking ni->mrec_lock, while ntfs_attr_record_resize(), ntfs_make_room_for_attr() and ntfs_resident_attr_record_add() memmove() the same base_ni->mrec buffer under that lock. map_mft_record() only takes a reference and does not serialize, so the reader can observe torn attribute length and offset fields while a writer is relocating the records. KCSAN reports the race between the mmap read fault path and both link() and unlink(): BUG: KCSAN: data-race in ntfs_attr_find / ntfs_attr_record_resize write to 0xffff888100af1018 of 4 bytes by task 96 on cpu 1: ntfs_attr_record_resize+0xd2/0x130 ntfs_attr_record_rm+0xad/0x530 ntfs_delete+0x224/0x640 ntfs_unlink+0x14d/0x280 vfs_unlink+0x157/0x520 read to 0xffff888100af1018 of 4 bytes by task 95 on cpu 0: ntfs_attr_find+0x104/0x5b0 ntfs_attr_lookup+0x39c/0x10c0 ntfs_read_iomap_begin_resident+0xc6/0x230 ntfs_read_iomap_begin+0x5d/0xa0 iomap_iter+0x2e2/0x6e0 iomap_read_folio+0x147/0x2a0 ntfs_read_folio+0x108/0x170 filemap_read_folio+0x35/0x100 filemap_fault+0x993/0x1000 value changed: 0x00000250 -> 0x000001f0 The address is mrec + 0x18, i.e. mft_record.bytes_in_use, and the change is the 96 bytes of one $FILE_NAME attribute being removed. Keep base_ni->mrec_lock from the resident read iomap lookup through iomap_end(). This protects both the attribute walk and the subsequent copy from iomap->inline_data, which points into the MFT record. The non-resident path is left alone: ntfs_lookup() already holds the directory inode's mrec_lock when it reads an index folio through read_mapping_folio(), and taking the lock in the shared wrapper deadlocks there with recursive locking on mrec_lock. The comment above the read_mapping_folio() call in fs/ntfs/dir.c notes the same hazard. The seek path uses the same lookup helper but does not dereference iomap->inline_data. Release the lock before returning from that path, whereas the regular read path records base_ni in iomap->private and releases the lock from its iomap_end() callback. Tested with a reproducer that faults in a 16-byte resident file while another thread runs link()/unlink() on it. Before: 40 KCSAN reports in about one second. After: no reports in 180 seconds over 206,090 read iterations and 423,540 link/unlink cycles. A PROVE_LOCKING build shows no lockdep splat with the same reproducer running for 60 seconds.
INFO
Published Date :
Sept. 17, 2026, 5:17 p.m.
Last Modified :
Sept. 18, 2026, 6:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Acquire mrec_lock before reading MFT record.
- Release mrec_lock after reading is complete.
- Ensure lock is held during attribute walk.
- Do not hold lock for non-resident paths.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-90131.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/0400e0d50eb3be19c98323faa322b652e4ae3f99 | |
| https://git.kernel.org/stable/c/d9e00c457d4ab8ab59c6e4b8554c921260e4e16c |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-90131 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-90131
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-90131 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-90131 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 17, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: ntfs: serialize resident iomap reads with mrec_lock ntfs_read_iomap_begin_resident() walks the MFT record through ntfs_attr_lookup() -> ntfs_attr_find() without taking ni->mrec_lock, while ntfs_attr_record_resize(), ntfs_make_room_for_attr() and ntfs_resident_attr_record_add() memmove() the same base_ni->mrec buffer under that lock. map_mft_record() only takes a reference and does not serialize, so the reader can observe torn attribute length and offset fields while a writer is relocating the records. KCSAN reports the race between the mmap read fault path and both link() and unlink(): BUG: KCSAN: data-race in ntfs_attr_find / ntfs_attr_record_resize write to 0xffff888100af1018 of 4 bytes by task 96 on cpu 1: ntfs_attr_record_resize+0xd2/0x130 ntfs_attr_record_rm+0xad/0x530 ntfs_delete+0x224/0x640 ntfs_unlink+0x14d/0x280 vfs_unlink+0x157/0x520 read to 0xffff888100af1018 of 4 bytes by task 95 on cpu 0: ntfs_attr_find+0x104/0x5b0 ntfs_attr_lookup+0x39c/0x10c0 ntfs_read_iomap_begin_resident+0xc6/0x230 ntfs_read_iomap_begin+0x5d/0xa0 iomap_iter+0x2e2/0x6e0 iomap_read_folio+0x147/0x2a0 ntfs_read_folio+0x108/0x170 filemap_read_folio+0x35/0x100 filemap_fault+0x993/0x1000 value changed: 0x00000250 -> 0x000001f0 The address is mrec + 0x18, i.e. mft_record.bytes_in_use, and the change is the 96 bytes of one $FILE_NAME attribute being removed. Keep base_ni->mrec_lock from the resident read iomap lookup through iomap_end(). This protects both the attribute walk and the subsequent copy from iomap->inline_data, which points into the MFT record. The non-resident path is left alone: ntfs_lookup() already holds the directory inode's mrec_lock when it reads an index folio through read_mapping_folio(), and taking the lock in the shared wrapper deadlocks there with recursive locking on mrec_lock. The comment above the read_mapping_folio() call in fs/ntfs/dir.c notes the same hazard. The seek path uses the same lookup helper but does not dereference iomap->inline_data. Release the lock before returning from that path, whereas the regular read path records base_ni in iomap->private and releases the lock from its iomap_end() callback. Tested with a reproducer that faults in a 16-byte resident file while another thread runs link()/unlink() on it. Before: 40 KCSAN reports in about one second. After: no reports in 180 seconds over 206,090 read iterations and 423,540 link/unlink cycles. A PROVE_LOCKING build shows no lockdep splat with the same reproducer running for 60 seconds. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90131.json">CVE-2026-90131</a> Added Reference https://git.kernel.org/stable/c/0400e0d50eb3be19c98323faa322b652e4ae3f99 Added Reference https://git.kernel.org/stable/c/d9e00c457d4ab8ab59c6e4b8554c921260e4e16c