CVE intelligence

CVE-2025-21656

Vulnerability intelligence

Published Jan 21, 2025Sources checked Nov 10, 2026

5.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2025-21656 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

Ubuntu Security Notices guidance

Vendor revision: Nov 10, 2026

This update corrects flaws in the following subsystems: - x86 architecture; - Hardware monitoring drivers; - OCFS2 file system; - IPv4 networking; - Ethernet bridge; - Netfilter; - XFRM subsystem; (CVE-2025-21656, CVE-2026-63940, CVE-2026-74350, CVE-2026-98432, CVE-2026-99999)

Ubuntu Security Notices guidance

Vendor revision: Nov 10, 2026

This update corrects flaws in the following subsystems: - x86 architecture; - Hardware monitoring drivers; - OCFS2 file system; (CVE-2025-21656, CVE-2026-63940, CVE-2026-74350)

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-2025-21656?

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

hwmon: (drivetemp) Fix driver producing garbage data when SCSI errors occur

scsi_execute_cmd() function can return both negative (linux codes) and positive (scsi_cmnd result field) error codes.

Currently the driver just passes error codes of scsi_execute_cmd() to hwmon core, which is incorrect because hwmon only checks for negative error codes. This leads to hwmon reporting uninitialized data to userspace in case of SCSI errors (for example if the disk drive was disconnected).

This patch checks scsi_execute_cmd() output and returns -EIO if it's error code is positive.

[groeck: Avoid inline variable declaration for portability]

Source: NVD