CVE-2025-21983: Linux kernel · mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 29 Oct 2026, 23:17 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 Apr 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
- nvd.nist.gov/vuln/detail/CVE-2025-21983 (opens in a new tab)
- git.kernel.org/stable/c/656e35bf66a11e1adde44c4c12050086dc39f241 (opens in a new tab)
- git.kernel.org/stable/c/a74979dce9e9c61f6d797c3761020252c4d8dc63 (opens in a new tab)
- git.kernel.org/stable/c/dfd3df31c9db752234d7d2e09bef2aeabb643ce4 (opens in a new tab)