CVE-2025-38217: Linux kernel · hwmon: (ftsteutates) Fix TOCTOU race in fts_read()
Source GCVE Database
Not known to be exploited · CVSS 4.7 Medium.
Data as of 13 Nov 2026, 19:59 UTC
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Jul 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 is available that eliminates the race condition by reading the shared variable once into a local variable and adding bounds checking before bit shifting. Users should apply the official Linux kernel patches that address this issue. Since no vendor advisory or patch links are provided in the input, confirm patch availability from the Linux kernel official sources. No additional mitigations are indicated.
Description
CVE-2025-38217 is a medium severity vulnerability in the Linux kernel's hwmon subsystem affecting the fts_read() function. It involves a Time-of-Check to Time-of-Use (TOCTOU) race condition due to unsynchronized access to a shared variable, which can lead to undefined behavior such as kernel crashes. The issue arises when the variable data->fan_source[channel] is checked and then used without locking, allowing concurrent modification by another thread. The vulnerability has been fixed by reading the variable once into a local variable and adding bounds checking before bit shifting.
References
- nvd.nist.gov/vuln/detail/CVE-2025-38217 (opens in a new tab)
- git.kernel.org/stable/c/14c9ede9ca4cd078ad76a6ab9617b81074eb58bf (opens in a new tab)
- git.kernel.org/stable/c/4d646f627d3b7ed1cacca66e598af8bcd632d465 (opens in a new tab)
- git.kernel.org/stable/c/83e2ba8971ccd8fc08319fc7593288f070d80a76 (opens in a new tab)
- git.kernel.org/stable/c/d95d87841d2a575bed3691884e8fedef57d7710d (opens in a new tab)