CVE-2026-98722 mtd: block2mtd: Fix divide error when erase_size is zero
A local attacker with high privileges can cause a kernel crash by setting a zero erase size in the block2mtd module parameter.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98722?
CVE-2026-98722 is a denial of service vulnerability in Linux, published on 18 Oct 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:
mtd: block2mtd: Fix divide error when erase_size is zero
The erase size is parsed from the "block2mtd" module parameter and can be set to zero. add_device() then evaluates
if (size % erase_size)
with a zero divisor, which triggers a divide error:
divide error: 0000 [#1] PREEMPT SMP PTI RIP: 0010:add_device drivers/mtd/devices/block2mtd.c:296 [inline] RIP: 0010:block2mtd_setup2+0x592/0xda0 drivers/mtd/devices/block2mtd.c:459 Call Trace: block2mtd_setup+0x27/0xe0 drivers/mtd/devices/block2mtd.c:476 param_attr_store+0x214/0x310 kernel/params.c:589 module_attr_store+0x65/0x90 kernel/params.c:904 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345 ...
Reject a zero erase size before performing the modulo operation so the existing "erasesize must be a divisor of device size" error path reports the invalid argument and frees the device.
Which versions are affected by CVE-2026-98722?
How do I fix CVE-2026-98722?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-98722 being exploited?
There is no known exploitation of CVE-2026-98722 in the wild and no public exploit code.
Sources
Also known as AZL-108917, BELL-CVE-2026-98722, DEBIAN-CVE-2026-98722, GHSA-9h6m-c947-v865, UBUNTU-CVE-2026-98722.