Bug 2464382 (CVE-2026-31716) - CVE-2026-31716 kernel: fs/ntfs3: validate rec->used in journal-replay file record check
Summary: CVE-2026-31716 kernel: fs/ntfs3: validate rec->used in journal-replay file re...
Keywords:
Status: NEW
Alias: CVE-2026-31716
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-01 15:03 UTC by OSIDB Bzimport
Modified: 2026-05-01 20:32 UTC (History)
2 users (show)

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


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-05-01 15:03:35 UTC
In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: validate rec->used in journal-replay file record check

check_file_record() validates rec->total against the record size but
never validates rec->used.  The do_action() journal-replay handlers read
rec->used from disk and use it to compute memmove lengths:

  DeleteAttribute:    memmove(attr, ..., used - asize - roff)
  CreateAttribute:    memmove(..., attr, used - roff)
  change_attr_size:   memmove(..., used - PtrOffset(rec, next))

When rec->used is smaller than the offset of a validated attribute, or
larger than the record size, these subtractions can underflow allowing
us to copy huge amounts of memory in to a 4kb buffer, generally
considered a bad idea overall.

This requires a corrupted filesystem, which isn't a threat model the
kernel really needs to worry about, but checking for such an obvious
out-of-bounds value is good to keep things robust, especially on journal
replay

Fix this up by bounding rec->used correctly.

This is much like commit b2bc7c44ed17 ("fs/ntfs3: Fix slab-out-of-bounds
read in DeleteIndexEntryRoot") which checked different values in this
same switch statement.


Note You need to log in before you can comment on or make changes to this bug.