CVE-2021-47471: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: drm: mxsfb: Fix NULL pointer dereference crash on unload The mxsfb->crtc.funcs may already be NULL when unloading the driver, in which case calling mxsfb_irq_disable() via drm_irq_uninstall() from mxsfb_unload() leads to NULL pointer dereference. Since all we care about is masking the IRQ and mxsfb->base is still valid, just use that to clear and mask the IRQ.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.10 — 5.10.76
linux	linux_kernel	5.11 — 5.14.15
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/3cfc183052c3dbf8eae57b6c1685dab00ed3db4a https://git.kernel.org/stable/c/b0e6db0656ddfd8bb57303c2ef61ee1c1cc694a8 https://git.kernel.org/stable/c/f40c2281d2c0674d32ba732fee45222d76495472 https://git.kernel.org/stable/c/3cfc183052c3dbf8eae57b6c1685dab00ed3db4a https://git.kernel.org/stable/c/b0e6db0656ddfd8bb57303c2ef61ee1c1cc694a8 https://git.kernel.org/stable/c/f40c2281d2c0674d32ba732fee45222d76495472

Frequently Asked Questions

What is CVE-2021-47471? +

In the Linux kernel, the following vulnerability has been resolved: drm: mxsfb: Fix NULL pointer dereference crash on unload The mxsfb->crtc.funcs may already be NULL when unloading the driver, in which case calling mxsfb_irq_disable() via drm_irq_uninstall() from mxsfb_unload() leads to NULL pointer dereference. Since all we care about is masking the IRQ and mxsfb->base is still valid, just use that to clear and mask the IRQ. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47471? +

CVE-2021-47471 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-47471? +

CVE-2021-47471 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-2021-47471? +

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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