CVE-2025-68293 mm/huge_memory: fix NULL pointer deference when splitting folio
A NULL pointer dereference in the Linux kernel's huge memory management allows local attackers to cause a system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68293?
CVE-2025-68293 is a vulnerability in Linux, published on 16 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: fix NULL pointer deference when splitting folio
Commit c010d47f107f ("mm: thp: split huge page to any lower order pages") introduced an early check on the folio's order via mapping->flags before proceeding with the split work.
This check introduced a bug: for shmem folios in the swap cache and truncated folios, the mapping pointer can be NULL. Accessing mapping->flags in this state leads directly to a NULL pointer dereference.
This commit fixes the issue by moving the check for mapping != NULL before any attempt to access mapping->flags.
Which versions are affected by CVE-2025-68293?
How do I fix CVE-2025-68293?
Apply the vendor's patch.
Is CVE-2025-68293 being exploited?
There is no known exploitation of CVE-2025-68293 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-68293, DEBIAN-CVE-2025-68293, GHSA-r3mj-3wvr-4c72, ROOT-OS-DEBIAN-13-CVE-2025-68293, UBUNTU-CVE-2025-68293.