CVE-2021-47383 Affecting kernel-default-base package, versions <5.3.18-150200.24.194.1.150200.9.99.1


Severity

Recommended
medium

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-SLES152-KERNELDEFAULTBASE-7364592
  • published25 Jun 2024
  • disclosed24 Jun 2024

Introduced: 24 Jun 2024

CVE-2021-47383  (opens in a new tab)

How to fix?

Upgrade SLES:15.2 kernel-default-base to version 5.3.18-150200.24.194.1.150200.9.99.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-base package and not the kernel-default-base package as distributed by SLES. See How to fix? for SLES:15.2 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