Bug 2482052 (CVE-2026-45915) - CVE-2026-45915 kernel: fat: avoid parent link count underflow in rmdir
Summary: CVE-2026-45915 kernel: fat: avoid parent link count underflow in rmdir
Keywords:
Status: NEW
Alias: CVE-2026-45915
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:08 UTC by OSIDB Bzimport
Modified: 2026-05-28 01:38 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-05-27 15:08:57 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fat: avoid parent link count underflow in rmdir

Corrupted FAT images can leave a directory inode with an incorrect
i_nlink (e.g. 2 even though subdirectories exist). rmdir then
unconditionally calls drop_nlink(dir) and can drive i_nlink to 0,
triggering the WARN_ON in drop_nlink().

Add a sanity check in vfat_rmdir() and msdos_rmdir(): only drop the
parent link count when it is at least 3, otherwise report a filesystem
error.
Comment 1 Keith Grant 2026-05-28 01:35:16 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052723-CVE-2026-45915-ddf9@gregkh/T
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