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VulnerabilityPublished Updated

CVE-2025-21983: Linux kernel · mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq

Source GCVE Database

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Not known to be exploited · CVSS 7.8 High.

Data as of 29 Oct 2026, 23:17 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Apr 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 29 Oct 2026.

What to do

AI-suggested

A fix is available that switches the kvfree_rcu() API to use the WQ_MEM_RECLAIM workqueue instead of the system_unbound_wq. Users should apply the official Linux kernel patches that implement this change to resolve the issue.

Description

CVE-2025-21983 is a high-severity vulnerability in the Linux kernel's memory management subsystem. It involves the kvfree_rcu() API using an inappropriate system workqueue (system_unbound_wq) for reclaiming memory, which can lead to kernel warnings and potential instability. The issue is addressed by switching to the WQ_MEM_RECLAIM workqueue, which is designed specifically for memory reclaim operations, thereby preventing workqueue framework rule violations.

References

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