CVE-2025-21886: Linux kernel · RDMA/mlx5: Fix implicit ODP hang on parent deregistration
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 30 Oct 2026, 14:18 UTC
Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 27 Mar 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 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Linux Linux | Affected
| Fixed in– |
AI-suggested
A fix is available that properly manages the reference count during implicit MR parent deregistration. Users should apply the updated Linux kernel version containing this patch to resolve the hang issue. No alternative mitigations are indicated.
Description
CVE-2025-21886 addresses a hang issue in the Linux kernel's RDMA mlx5 driver caused by improper reference count management during parent deregistration of implicit on-demand paging (ODP) memory regions. The flaw could cause tasks to block indefinitely. The fix ensures proper decrement of the reference count to prevent this hang.
References
- git.kernel.org/stable/c/641e50b27e87d7cd0d194f7a164703de599055b1 (opens in a new tab)
- git.kernel.org/stable/c/cb96ae783e7249e8e5a50c22952c0bb2983133df (opens in a new tab)
- git.kernel.org/stable/c/a095ede2daca49d15e74d66d014883f2fa8bb924 (opens in a new tab)
- git.kernel.org/stable/c/3d8c6f26893d55fab218ad086719de1fc9bb86ba (opens in a new tab)