# CVE-2026-98722: Linux kernel block2mtd divide-by-zero on zero erase_size

Source: https://junglewise.ai/threats/cve-2026-98722-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-18. Updated: 2026-10-18  
License: CC BY 4.0 with a link back

CVE-2026-98722 · Severity: info · Published 2026-10-18

The Linux kernel's block2mtd module converts block devices into memory technology devices (MTD) used for flash memory access. A flaw allows a user to set the erase size parameter to zero, causing a divide-by-zero error that crashes the system. An attacker with the ability to load kernel modules or modify module parameters could trigger this denial of service.

Technologies: [Unknown Linux kernel](https://junglewise.ai/threats/technologies/unknown-linux-kernel). Vendors: [Unknown](https://junglewise.ai/threats/vendors/unknown).

## Quick answers

**Is CVE-2026-98722 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-98722 being exploited in the wild.

**How severe is CVE-2026-98722?** Informational severity, published 18 October 2026.

**Which products and versions are affected?** Unknown Linux kernel affected kernels through commit ea6d833a3fdd onwards; fix in commit b5965c4221165045e19736794ca5f48ae3d67142.

**Is there a fix for CVE-2026-98722?** Yes: fixed in Fixed in commit b5965c4221165045e19736794ca5f48ae3d67142 (merged to multiple stable kernel branches). Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-98722 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-98722?** Check whether you run Unknown Linux kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Fixed in commit b5965c4221165045e19736794ca5f48ae3d67142 (merged to multiple stable kernel branches)

## Technical details

The vulnerability is a divide-by-zero error in the block2mtd module's add_device() function in drivers/mtd/devices/block2mtd.c. The erase_size parameter is not validated before being used as a divisor in a modulo operation (size % erase_size). An attacker can set erase_size to zero via the block2mtd module parameter, triggering a kernel panic. The fix adds a check to reject zero erase_size before the modulo operation.

## Affected products

- <UNKNOWN> Linux kernel affected kernels through commit ea6d833a3fdd onwards; fix in commit b5965c4221165045e19736794ca5f48ae3d67142

## Timeline

- 2026-10-18: disclosed

## References

- [https://git.kernel.org/stable/c/21d0f05989bf0d5cef57b467a7fa4feefbd7236a](https://git.kernel.org/stable/c/21d0f05989bf0d5cef57b467a7fa4feefbd7236a)
- [https://git.kernel.org/stable/c/826170a49ca1315af6b293a02200585b1e2186d9](https://git.kernel.org/stable/c/826170a49ca1315af6b293a02200585b1e2186d9)

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