# CVE-2026-72203: ntfs: skip extent mft records in writeback to prevent deadlock

CVE-2026-72203 is fixed in linux on 1 platform by DEBIAN-CVE-2026-72203 (version 7.1.5-1), released August 15, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-72203
- Priority: High
- CVSS: 7.5 (Moderate)
- EPSS: 0.0063
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 15, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-72203

## Description

In the Linux kernel, the following vulnerability has been resolved:  ntfs: skip extent mft records in writeback to prevent deadlock  This patch fixes the ABBA deadlock between extent_lock and extent mrec_lock triggered by xfstests generic/113, that occurs since the commit 6994acf33bae ("ntfs: use base mft_no when looking up base inode for 		extent record").  Path A (inode writeback):   VFS writeback     -> ntfs_write_inode()       -> __ntfs_write_inode()         -> mutex_lock(&ni->extent_lock)         -> mutex_lock(&tni->mrec_lock)  Path B (MFT folio writeback):   VFS writeback of $MFT dirty folios     -> ntfs_mft_writepages()       -> ntfs_write_mft_block()         -> ntfs_may_write_mft_record()           -> holds one extent mrec_lock from a previous iteration           -> tries to acquire another base inode extent_lock  By removing all extent_lock and extent mrec_lock acquisition from the MFT folio writeback path, the ABBA lock ordering is eliminated:  Path A: __ntfs_write_inode(): extent_lock -> mrec_lock Path B (removed): ntfs_write_mft_block(): mrec_lock -> extent_lock  Path B is always redundant for extent records because:  1. mark_mft_record_dirty(ext_ni) does NOT dirty the MFT folio.    It only sets NInoDirty(ext_ni) and marks the base VFS inode dirty    via __mark_inode_dirty(I_DIRTY_DATASYNC), which triggers Path A.    Therefore, normal extent modifications never create a situation where    the MFT folio is dirty and Path B is not scheduled.  2. The MFT folio only gets dirtied via ntfs_mft_mark_dirty() inside    ntfs_mft_record_alloc(). But all identified callers in attrib.c    (ntfs_attr_add, ntfs_attr_record_move_away,    ntfs_attr_make_non_resident, ntfs_attr_record_resize) follow through    with mark_mft_record_dirty(), which triggers Path A to write the    complete record.  3. ntfs_evict_big_inode() calls ntfs_commit_inode() before freeing extent    inodes, ensuring all dirty extents are flushed via Path A before the    base inode leaves the icache.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.5-1 | [DEBIAN-CVE-2026-72203](https://patchblox.com/security/data/fix/linux/debian-cve-2026-72203.md) | Aug 15, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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