CVE-2021-47386: linux kernel Null Dereference — Fix

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]

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 5.4.151
linux	linux_kernel	5.5 — 5.10.71
linux	linux_kernel	5.11 — 5.14.10
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/16887ae4e3defd2c4e7913b6c539f33eaf4eac5c https://git.kernel.org/stable/c/44d3c480e4e2a75bf6296a18b4356157991ccd80 https://git.kernel.org/stable/c/516d9055039017a20a698103be2b556b4c976bb8 https://git.kernel.org/stable/c/943c15ac1b84d378da26bba41c83c67e16499ac4 https://git.kernel.org/stable/c/16887ae4e3defd2c4e7913b6c539f33eaf4eac5c https://git.kernel.org/stable/c/44d3c480e4e2a75bf6296a18b4356157991ccd80 https://git.kernel.org/stable/c/516d9055039017a20a698103be2b556b4c976bb8 https://git.kernel.org/stable/c/943c15ac1b84d378da26bba41c83c67e16499ac4

Frequently Asked Questions

What is CVE-2021-47386? +

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] It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47386? +

CVE-2021-47386 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2021-47386? +

CVE-2021-47386 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-47386? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2021-47386