CVE-2025-68348 block: fix memory leak in __blkdev_issue_zero_pages
A memory leak in the Linux kernel block layer allows local attackers to cause denial of service by triggering fatal signals during zero-page operations.
- 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-2025-68348?
CVE-2025-68348 is a memory corruption vulnerability in Linux, published on 24 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:
block: fix memory leak in __blkdev_issue_zero_pages
Move the fatal signal check before bio_alloc() to prevent a memory leak when BLKDEV_ZERO_KILLABLE is set and a fatal signal is pending.
Previously, the bio was allocated before checking for a fatal signal. If a signal was pending, the code would break out of the loop without freeing or chaining the just-allocated bio, causing a memory leak.
This matches the pattern already used in __blkdev_issue_write_zeroes() where the signal check precedes the allocation.
Which versions are affected by CVE-2025-68348?
How do I fix CVE-2025-68348?
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-2025-68348 being exploited?
There is no known exploitation of CVE-2025-68348 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-68348, DEBIAN-CVE-2025-68348, GHSA-9hww-p592-6h89, UBUNTU-CVE-2025-68348.