CVE-2026-45914

In the Linux kernel, the following vulnerability has been resolved:

Revert hwmon: (ibmpex) fix use-after-free in high/low store

This reverts commit 6946c726c3f4c36f0f049e6f97e88c510b15f65d.

Jean Delvare points out that the patch does not completely fix the reported problem, that it in fact introduces a (new) race condition, and that it may actually not be needed in the first place.

Various AI reviews agree. Specific and relevant AI feedback:

This reordering sets the driver data to NULL before removing the sensor attributes in the loop below.

ibmpex_show_sensor() retrieves this driver data via dev_get_drvdata() but does not check if it is NULL before dereferencing it to access data->sensors[].

If a userspace process reads a sensor file (like temp1_input) while this delete function is running, could it race with the dev_set_drvdata(…, NULL) call here and crash in ibmpex_show_sensor()?

Would it be safer to keep the original order where device_remove_file() is called before clearing the driver data? device_remove_file() should wait for any active sysfs callbacks to complete, which might already prevent the use-after-free this patch intends to fix.

Revert the offending patch. If it can be shown that the originally reported alleged race condition does indeed exist, it can always be re-introduced with a complete fix.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/05112ba67c824ab416cd54307c0b50aba9f0047a
• https://git.kernel.org/stable/c/14a38784e09aebc21207dc32fffa05247fc3dd64
• https://git.kernel.org/stable/c/894d9c7aab68fd0c70c78b1d03c8fa589fb0f67d
• https://git.kernel.org/stable/c/8bde3e395a85017f12af2b0ba5c3684f5af9c006
• https://git.kernel.org/stable/c/914b47c9b824d3d74f31c764163edf93302100b1
• https://git.kernel.org/stable/c/efd68429f23fb4015b0ebc2392334059e06fad18
• https://git.kernel.org/stable/c/f448acd86835a650f9ea83460b9ca347d3aafba5