Bug 2517033 (CVE-2026-74551) - CVE-2026-74551 kernel: hwmon: (nzxt-smart2) DMA-align output buffer
Summary: CVE-2026-74551 kernel: hwmon: (nzxt-smart2) DMA-align output buffer
Keywords:
Status: NEW
Alias: CVE-2026-74551
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 12:46 UTC by OSIDB Bzimport
Modified: 2026-08-19 19:03 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-08-15 12:46:04 UTC
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.

Comment 1 Mauro Matteo Cascella 2026-08-19 18:58:20 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081550-CVE-2026-74551-720e@gregkh/T


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