CVE-2025-21999: Linux kernel · proc: fix UAF in proc_get_inode()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 10 Nov 2026, 13:47 UTC
Sources agree
| CNA (Linux) | CVSS 3.1 | 7.8 |
|---|---|---|
| CISA-ADP | CVSS 3.1 | 7.8 |
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 3 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 10 Nov 2026.
What to do
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel. Users and administrators should apply the official kernel updates that include this patch to resolve the use-after-free condition in proc_get_inode(). No additional mitigation steps are required once the patch is applied.
Description
CVE-2025-21999 is a use-after-free (UAF) vulnerability in the Linux kernel's proc filesystem, specifically in the proc_get_inode() function. The flaw arises from a race condition between module removal (rmmod) and inode instantiation for /proc entries. Dereferencing proc_ops of a module after it has been freed leads to a kernel crash (use-after-free).
References
- git.kernel.org/stable/c/eda279586e571b05dff44d48e05f8977ad05855d (opens in a new tab)
- git.kernel.org/stable/c/4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa (opens in a new tab)
- git.kernel.org/stable/c/966f331403dc3ed04ff64eaf3930cf1267965e53 (opens in a new tab)
- git.kernel.org/stable/c/63b53198aff2e4e6c5866a4ff73c7891f958ffa4 (opens in a new tab)
- git.kernel.org/stable/c/ede3e8ac90ae106f0b29cd759aadebc1568f1308 (opens in a new tab)
- git.kernel.org/stable/c/64dc7c68e040251d9ec6e989acb69f8f6ae4a10b (opens in a new tab)
- git.kernel.org/stable/c/654b33ada4ab5e926cd9c570196fefa7bec7c1df (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00045.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00030.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)