CVE-2026-74551 hwmon: (nzxt-smart2) DMA-align output buffer
A memory corruption vulnerability in the Linux kernel nzxt-smart2 driver allows attackers to corrupt adjacent memory via DMA cache line sharing on non-coherent architectures.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74551?
CVE-2026-74551 is a high-severity memory corruption vulnerability in Linux, published on 15 Aug 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:
hwmon: (nzxt-smart2) DMA-align output buffer
Sashiko reports:
When send_output_report() calls hid_hw_output_report(), the underlying USB HID core calls usb_interrupt_msg() which maps this buffer directly for DMA.
When the DMA mapping flushes or invalidates the cacheline, it will corrupt the adjacent variables (mutex, update_interval) 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 (CONFIG_DMA_API_DEBUG) will trigger runtime warnings for this violation.
Any operation that triggers send_output_report() (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 ARCH_DMA_MINALIGN to fix the problem.
Which versions are affected by CVE-2026-74551?
How do I fix CVE-2026-74551?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-74551 being exploited?
There is no known exploitation of CVE-2026-74551 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74551, DEBIAN-CVE-2026-74551, GHSA-3m5x-223v-jq2m, UBUNTU-CVE-2026-74551.