CVE-2021-47386: hwmon: (w83791d) Fix NULL pointer dereference by removing unnecessary structure field

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (w83791d) Fix NULL pointer dereference by removing unnecessary structure field If driver read val value sufficient for (val & 0x08) && (!(val & 0x80)) && ((val & 0x7) == ((val >> 4) & 0x7)) from device then Null pointer dereference occurs. (It is possible if tmp = 0b0xyz1xyz, where same literals mean same numbers) Also lm75[] does not serve a purpose anymore after switching to devm_i2c_new_dummy_device() in w83791d_detect_subclients(). The patch fixes possible NULL pointer dereference by removing lm75[]. Found by Linux Driver Verification project (linuxtesting.org). [groeck: Dropped unnecessary continuation lines, fixed multi-line alignment]

Affected products

Linux kernel: before 5.4.151; from 5.5 before 5.10.71; from 5.11 before 5.14.10; 5.15-rc1, 5.15-rc2, 5.15-rc3 — fixed in 5.10.71, 5.14.10, 5.4.151

How to fix

Upgrade to a fixed version: Linux kernel 5.10.71, 5.14.10, 5.4.151. Check the vendor advisory for mitigations.

References

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