CVE - CVE-2025-38217

CVE-ID
CVE-2025-38217	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: hwmon: (ftsteutates) Fix TOCTOU race in fts_read() In the fts_read() function, when handling hwmon_pwm_auto_channels_temp, the code accesses the shared variable data->fan_source[channel] twice without holding any locks. It is first checked against FTS_FAN_SOURCE_INVALID, and if the check passes, it is read again when used as an argument to the BIT() macro. This creates a Time-of-Check to Time-of-Use (TOCTOU) race condition. Another thread executing fts_update_device() can modify the value of data->fan_source[channel] between the check and its use. If the value is changed to FTS_FAN_SOURCE_INVALID (0xff) during this window, the BIT() macro will be called with a large shift value (BIT(255)). A bit shift by a value greater than or equal to the type width is undefined behavior and can lead to a crash or incorrect values being returned to userspace. Fix this by reading data->fan_source[channel] into a local variable once, eliminating the race condition. Additionally, add a bounds check to ensure the value is less than BITS_PER_LONG before passing it to the BIT() macro, making the code more robust against undefined behavior. This possible bug was found by an experimental static analysis tool developed by our team.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/14c9ede9ca4cd078ad76a6ab9617b81074eb58bf URL:https://git.kernel.org/stable/c/14c9ede9ca4cd078ad76a6ab9617b81074eb58bf MISC:https://git.kernel.org/stable/c/4d646f627d3b7ed1cacca66e598af8bcd632d465 URL:https://git.kernel.org/stable/c/4d646f627d3b7ed1cacca66e598af8bcd632d465 MISC:https://git.kernel.org/stable/c/83e2ba8971ccd8fc08319fc7593288f070d80a76 URL:https://git.kernel.org/stable/c/83e2ba8971ccd8fc08319fc7593288f070d80a76 MISC:https://git.kernel.org/stable/c/d95d87841d2a575bed3691884e8fedef57d7710d URL:https://git.kernel.org/stable/c/d95d87841d2a575bed3691884e8fedef57d7710d
Assigning CNA
kernel.org
Date Record Created
20250416	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250416)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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