Bug 2516688 (CVE-2026-72478) - CVE-2026-72478 kernel: fs/ntfs3: add bounds check to run_get_highest_vcn()
Summary: CVE-2026-72478 kernel: fs/ntfs3: add bounds check to run_get_highest_vcn()
Keywords:
Status: NEW
Alias: CVE-2026-72478
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 06:25 UTC by OSIDB Bzimport
Modified: 2026-08-19 18:14 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-08-15 06:25:53 UTC
In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: add bounds check to run_get_highest_vcn()

run_get_highest_vcn() parses a packed NTFS mapping-pairs buffer without
any length bound, relying solely on a 0x00 terminator to stop.  A
crafted $LogFile UpdateMappingPairs record whose embedded attribute
contains mapping-pairs runs without a terminator causes the function to
read past the slab allocation, triggering a KASAN slab-out-of-bounds
read on mount.

The sibling function run_unpack() received an analogous bounds-check in
commit b62567bca474 ("ntfs3: add buffer boundary checks to run_unpack()"),
but run_get_highest_vcn() was missed.

Take a run_buf_size parameter and reject any run header whose payload
would extend past the buffer end, mirroring the pattern used by
run_unpack().  The caller in fslog.c passes the remaining attribute
bytes after the mapping-pairs offset.

KASAN report (on mainline v7.1 merge window HEAD):

  BUG: KASAN: slab-out-of-bounds in run_get_highest_vcn+0x3c0/0x410
  Read of size 1 at addr ffff88800e2d5400 by task mount/72
  Call Trace:
   run_get_highest_vcn+0x3c0/0x410
   do_action.isra.0+0x3ba8/0x7b50
   log_replay+0x9ddd/0x10200
   ntfs_loadlog_and_replay+0x4ad/0x610
   ntfs_fill_super+0x214a/0x4540


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