CVE-2026-31716 fs/ntfs3: validate rec->used in journal-replay file record check
A missing validation in the Linux kernel NTFS3 driver allows memory corruption via a crafted filesystem, potentially leading to code execution or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-31716?
CVE-2026-31716 is a high-severity memory corruption vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-787
Which versions are affected by CVE-2026-31716?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31716?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-31716 being exploited?
There is no known exploitation of CVE-2026-31716 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31716, DEBIAN-CVE-2026-31716, GHSA-vw9p-6cf6-hxfh, ROOT-OS-DEBIAN-12-CVE-2026-31716, ROOT-OS-UBUNTU-2204-CVE-2026-31716, ROOT-OS-UBUNTU-2404-CVE-2026-31716 and 1 more.