CVE-2026-74551: hwmon: (nzxt-smart2) DMA-align output buffer
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (nzxt-smart2) DMA-align output buffer
Sashiko reports:
When sendoutputreport() calls hidhwoutputreport(), the underlying USB HID core calls usbinterruptmsg() which maps this buffer directly for DMA.
When the DMA mapping flushes or invalidates the cacheline, it will corrupt the adjacent variables (mutex, updateinterval) that were modified concurrently by the CPU. This causes memory corruption due to cacheline sharing on non-coherent CPU architectures (such as ARM or MIPS). The DMA API debugging tool (CONFIGDMAAPIDEBUG) will trigger runtime warnings for this violation.
Any operation that triggers sendoutputreport() (like setting a fan speed or updating the interval) causes the USB DMA mapping. On systems with non-coherent caches, this structural bug causes immediate and deterministic memory corruption.
Align the output buffer to ARCHDMAMINALIGN to fix the problem.
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Align the HID output buffer used by send_output_report() (via hid_hw_output_report() and usb_interrupt_msg() DMA mapping) to ARCH_DMA_MINALIGN to prevent memory corruption on non-coherent cache architectures.
Linux kernel HID core (hid_hw_output_report via send_output_report / usb_interrupt_msg) DMA alignment of output buffer = ARCH_DMA_MINALIGN
Event History
Frequently Asked Questions
What is the severity of CVE-2026-74551?
CVE-2026-74551 has a risk score of 47, indicating a moderate severity level.
How do I fix CVE-2026-74551?
To fix CVE-2026-74551, update the Linux kernel to the latest version that includes the patched code.
What systems are affected by CVE-2026-74551?
CVE-2026-74551 affects systems running the vulnerable versions of the Linux kernel that utilize the nzxt-smart2 hardware monitoring driver.
What is the impact of CVE-2026-74551?
The impact of CVE-2026-74551 could potentially allow unprivileged users to cause a denial of service or escalate privileges.
When was CVE-2026-74551 published?
CVE-2026-74551 was published on August 15, 2026.