# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-108917, BELL-CVE-2026-98722, DEBIAN-CVE-2026-98722, GHSA-9h6m-c947-v865, UBUNTU-CVE-2026-98722

## 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.

## Is CVE-2026-98722 being exploited?

There is no known exploitation of CVE-2026-98722 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98722 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-98722 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98722/ (Markdown: https://insights.sbomify.com/CVE-2026-98722/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98722
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98722
- OSV: https://osv.dev/vulnerability/CVE-2026-98722

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98722/
Summaries are generated and may contain mistakes; the official description above is the record.