NVD Vulnerability Detail
Search Exploit, PoC
CVE-2026-31716
Summary

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.

Publication Date May 1, 2026, 11:16 p.m.
Registration Date May 2, 2026, 4:06 a.m.
Last Update May 2, 2026, 12:24 a.m.
Related information, measures and tools
Common Vulnerabilities List