CVE-2025-38517: Linux kernel · lib/alloc_tag: do not acquire non-existent lock in alloc_tag_top_users()
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 13 Nov 2026, 20:17 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Aug 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 13 Nov 2026.
What to do
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel by adding a check to ensure alloc_tag_cttype is valid before acquiring the semaphore lock. Users should apply the official kernel updates that include this fix. Until patched, avoiding scenarios that trigger memory allocation failures in this context may reduce risk.
Description
CVE-2025-38517 is a vulnerability in the Linux kernel's alloc_tag subsystem where the function alloc_tag_top_users() attempts to acquire a semaphore lock on a non-existent alloc_tag_cttype object. This occurs when alloc_tag_cttype is not allocated due to memory profiling being disabled, uninitialized, or failed initialization. Attempting to acquire this non-existent lock leads to a kernel crash (general protection fault) during memory allocation failure scenarios.
References
- nvd.nist.gov/vuln/detail/CVE-2025-38517 (opens in a new tab)
- git.kernel.org/stable/c/22bf79c0c2301b6e15a688220284b147774d277e (opens in a new tab)
- git.kernel.org/stable/c/99af22cd34688cc0d535a1919e0bea4cbc6c1ea1 (opens in a new tab)
- git.kernel.org/stable/c/febc0b5dbabda414565bdfaaaa59d26f787d5fe7 (opens in a new tab)