CVE intelligence

CVE-2025-21904

Vulnerability intelligence

Published Apr 1, 2025Sources checked Oct 9, 2026

5.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2025-21904 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Aug 12, 2026

CBL-Mariner Releases

Vendor-listed releases

6.6.85.1-2
5.15.180.1-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.2%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2025-21904?

In the Linux kernel, the following vulnerability has been resolved:

caif_virtio: fix wrong pointer check in cfv_probe()

del_vqs() frees virtqueues, therefore cfv->vq_tx pointer should be checked for NULL before calling it, not cfv->vdev. Also the current implementation is redundant because the pointer cfv->vdev is dereferenced before it is checked for NULL.

Fix this by checking cfv->vq_tx for NULL instead of cfv->vdev before calling del_vqs().

Source: NVD