# CVE-2026-10679: Zephyr OS divide by zero in DesignWare SPI driver

Source: https://junglewise.ai/threats/cve-2026-10679-zephyr-os-divide-by-zero-in-designware-spi-driver  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-21. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-10679 · Severity: low · CVSS 3.3 · Published 2026-07-21

Zephyr is an open-source operating system designed for resource-constrained embedded devices. A flaw in the DesignWare SPI driver allows a local user or application with specific hardware permissions to crash the system by providing an invalid frequency value. This results in a system-wide restart or freeze, causing a denial of service, though it does not allow for data theft or unauthorized access.

Technologies: [Zephyr Project Zephyr OS](https://junglewise.ai/threats/technologies/zephyr-os). Vendors: [Zephyr Project](https://junglewise.ai/threats/vendors/zephyr-project).

## Quick answers

**Is CVE-2026-10679 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-10679 being exploited in the wild.

**How severe is CVE-2026-10679?** Low severity, with a CVSS score of 3.3, published 21 July 2026.

**Which products and versions are affected?** Zephyr Project Zephyr OS >= 1.8.0, <= 4.4.1.

**Is there a fix for CVE-2026-10679?** A patch was published on 2026-07-21. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-10679 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-10679?** Check whether you run Zephyr Project Zephyr OS 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.

## Technical details

A divide-by-zero vulnerability (CWE-369) exists in the DesignWare SPI driver (`drivers/spi/spi_dw.c`) within Zephyr OS. The `spi_transceive` syscall handler fails to validate the `frequency` field of the `spi_config` structure copied from userspace. When `frequency` is set to zero, the `SPI_DW_CLK_DIVIDER` macro performs an unsigned integer division by zero during hardware configuration. On architectures like ARM Cortex-M and ARC, this triggers a CPU exception and kernel fault. Exploitation requires `CONFIG_USERSPACE=y` and the calling thread must have been granted permission to the SPI device kernel object. The issue is fixed in version 4.5.0 by rejecting zero frequencies and those exceeding half the input clock frequency.

## Affected products

- Zephyr Project Zephyr OS >= 1.8.0, <= 4.4.1

## Timeline

- 2026-07-21: disclosed
- 2026-07-21: advisory
- 2026-07-21: patched

## References

- [https://github.com/zephyrproject-rtos/zephyr](https://github.com/zephyrproject-rtos/zephyr)
- [https://github.com/zephyrproject-rtos/zephyr/commit/65935885622b0e4a5dbe5b82504c30097eb75ce0](https://github.com/zephyrproject-rtos/zephyr/commit/65935885622b0e4a5dbe5b82504c30097eb75ce0)
- [https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3qcm-qwh2-v4hq](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3qcm-qwh2-v4hq)

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