CVE-2025-38217

System crash via unlocked fan-source reread

Published Jul 4, 2025 · Updated May 11, 2026

TOCTOU race in the Linux kernel's ftsteutates hwmon driver allows local users to crash the system or receive incorrect fan-source values. The fts_read() path checks data->fan_source[channel] and then rereads it without locking, allowing fts_update_device() to replace it with 0xff before BIT() shifts by 255. The affected code starts in 6.3, and exploitation requires low-privileged local access plus a concurrent driver update on applicable hardware.

CVSS severity4.7
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

TOCTOU race in the Linux kernel's ftsteutates hwmon driver allows local users to crash the system or receive incorrect fan-source values. The fts_read() path checks data->fan_source[channel] and then rereads it without locking, allowing fts_update_device() to replace it with 0xff before BIT() shifts by 255. The affected code starts in 6.3, and exploitation requires low-privileged local access plus a concurrent driver update on applicable hardware.

The record

CVE
CVE-2025-38217
Published
Jul 4, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-367, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 4, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1c5759d8ce054961b454af69568a41e7e3210ee1 <14c9ede9ca4cd078ad76a6ab9617b81074eb58bf
  2. Affected versionversion=1c5759d8ce054961b454af69568a41e7e3210ee1 <4d646f627d3b7ed1cacca66e598af8bcd632d465
  3. Affected versionversion=1c5759d8ce054961b454af69568a41e7e3210ee1 <83e2ba8971ccd8fc08319fc7593288f070d80a76
  4. Affected versionversion=1c5759d8ce054961b454af69568a41e7e3210ee1 <d95d87841d2a575bed3691884e8fedef57d7710d
  5. Affected versionversion=6.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1c5759d8ce054961b454af69568a41e7e3210ee1 <14c9ede9ca4cd078ad76a6ab9617b81074eb58bf; version=1c5759d8ce054961b454af69568a41e7e3210ee1 <4d646f627d3b7ed1cacca66e598af8bcd632d465; version=1c5759d8ce054961b454af69568a41e7e3210ee1 <83e2ba8971ccd8fc08319fc7593288f070d80a76; version=1c5759d8ce054961b454af69568a41e7e3210ee1 <d95d87841d2a575bed3691884e8fedef57d7710d; version=6.3

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
5.3SUSECVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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