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VulnerabilityPublished Updated

CVE-2025-38517: Linux kernel · lib/alloc_tag: do not acquire non-existent lock in alloc_tag_top_users()

Source GCVE Database

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Not known to be exploited · CVSS 5.5 Medium.

Data as of 13 Nov 2026, 20:17 UTC

CVSS 3.1 base score
5.5Medium
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:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Aug 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 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

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