CVE-2021-47383 Affecting kernel-devel package, versions <0:5.14.0-427.42.1.el9_4


Severity

Recommended
medium

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-ALMALINUX9-KERNELDEVEL-8333973
  • published4 Nov 2024
  • disclosed30 Oct 2024

Introduced: 30 Oct 2024

CVE-2021-47383  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 kernel-devel to version 0:5.14.0-427.42.1.el9_4 or higher.
This issue was patched in ALSA-2024:8617.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-devel package and not the kernel-devel package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

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

tty: Fix out-of-bound vmalloc access in imageblit

This issue happens when a userspace program does an ioctl FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct containing only the fields xres, yres, and bits_per_pixel with values.

If this struct is the same as the previous ioctl, the vc_resize() detects it and doesn't call the resize_screen(), leaving the fb_var_screeninfo incomplete. And this leads to the updatescrollmode() calculates a wrong value to fbcon_display->vrows, which makes the real_y() return a wrong value of y, and that value, eventually, causes the imageblit to access an out-of-bound address value.

To solve this issue I made the resize_screen() be called even if the screen does not need any resizing, so it will "fix and fill" the fb_var_screeninfo independently.

CVSS Scores

version 3.1