CVE-2025-38074: vhost-scsi: protect vq->log_used with vq->mutex

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-07-30

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.

Affected products

Debian Linux: 11.0
Linux kernel: before 5.10.240; from 5.11 before 5.15.189; from 5.16 before 6.1.146; from 6.2 before 6.6.93; from 6.7 before 6.12.31; from 6.13 before 6.14.9 — fixed in 5.10.240, 5.15.189, 6.1.146, 6.12.31, 6.14.9, 6.6.93

How to fix

Upgrade to a fixed version: Linux kernel 5.10.240, 5.15.189, 6.1.146, 6.12.31. Check the vendor advisory for mitigations.

References

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