CVE-2026-10679: The DesignWare SPI driver (drivers/spi/spi_dw.c) computed the SPI BAUDR clock divider as info->clock_frequency / config->frequency without validating config->fr

The DesignWare SPI driver (drivers/spi/spi_dw.c) computed the SPI BAUDR clock divider as info->clock_frequency / config->frequency without validating config->fr

The DesignWare SPI driver (drivers/spi/spi_dw.c) computed the SPI BAUDR clock divider as info->clock_frequency / config->frequency without validating config->frequency. spi_transceive is a Zephyr __syscall and its verify handler (drivers/spi/spi_handlers.c) copies the caller-supplied spi_config from userspace without checking the frequency field, so a userspace thread that has been granted access to a DesignWare SPI device kernel object can pass frequency = 0 and trigger an unsigned integer divide-by-zero in spi_dw_configure(). On Cortex-M Mainline (SCB->CCR.DIV_0_TRP is set in z_arm_fault_init()) and on ARC (a dedicated __ev_div_zero vector) this raises a CPU exception, resulting in a kernel fault and local denial of service. The fix rejects zero frequency and frequencies above clock_frequency / 2 (the DesignWare SSI databook minimum SCKDIV of 2) with -EINVAL. The defect affects all Zephyr releases up to and including v4.4.0; exploitation requires CONFIG_USERSPACE=y and an unprivileged thread already granted SPI driver permission. There is no memory-corruption or information-disclosure impact.

Description from the National Vulnerability Database, published by vulnerabilities@zephyrproject.org

What it means for a small business

If your business uses zephyr, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.14%, higher than 3% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 28, 2026, updated daily.

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Sources

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