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VulnerabilityPublished Updated

CVE-2025-21745: Linux kernel · blk-cgroup: Fix class @block_class's subsystem refcount leakage

Affects Linux kernelSource GCVE Database

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Not known to be exploited.

Data as of 10 Nov 2026, 14:48 UTC

Severity
Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Feb 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

What to do

AI-suggested

A fix is available that corrects the iteration process by adding the missing class_dev_iter_exit() call. Users should apply the official Linux kernel update that includes this fix to resolve the reference count leakage.

Description

A vulnerability in the Linux kernel's blk-cgroup subsystem caused a subsystem reference count leakage due to improper iteration handling over block devices. The issue was fixed by ensuring the iteration ends correctly with class_dev_iter_exit().

References

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