CVE-2026-72105 dm-log: fix a bitset_size overflow on 32bit machines
An integer overflow in the Linux kernel dm-log module on 32-bit systems can cause a denial of service by wrapping the bitmap size to zero.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72105?
CVE-2026-72105 is a high-severity vulnerability in Linux, published on 15 Aug 2026. 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:
dm-log: fix a bitset_size overflow on 32bit machines
Commit c20e36b7631d ("dm log: fix out-of-bounds write due to region_count overflow") made sure that region_count could fit in an unsigned int. But the bitmap memory isn't allocated based on region_count. It uses bitset_size (a size_t variable). The first step of calculating bitset_size is to set it to region_count, rounded up to a multiple of BITS_PER_LONG. If region_size is less than BITS_PER_LONG smaller than UINT_MAX, it will get rounded up to 2^32. On a 32bit architecture, this will make bitset_size wrap around to 0 and fail, despite region_count being valid.
Since bitset_size gets divided by 8, it can hold any valid region_count. It just needs a special case to handle the rollover. If it is 0, the value rolled over, and bitset size should be set to the number of bytes needed to hold 2^32 bits.
Weakness: CWE-190
Which versions are affected by CVE-2026-72105?
How do I fix CVE-2026-72105?
Apply the vendor's patch.
Is CVE-2026-72105 being exploited?
There is no known exploitation of CVE-2026-72105 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72105, DEBIAN-CVE-2026-72105, GHSA-gg95-xc64-46gm, UBUNTU-CVE-2026-72105.