CVE-2021-47383

CVE Details

Release Date:

2024-05-21

Description

In the Linux kernel, the following vulnerability has been resolved:\ntty: Fix out-of-bound vmalloc access in imageblit\nThis issue happens when a userspace program does an ioctl\nFBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct\ncontaining only the fields xres, yres, and bits_per_pixel\nwith values.\nIf this struct is the same as the previous ioctl, the\nvc_resize() detects it and doesn't call the resize_screen(),\nleaving the fb_var_screeninfo incomplete. And this leads to\nthe updatescrollmode() calculates a wrong value to\nfbcon_display->vrows, which makes the real_y() return a\nwrong value of y, and that value, eventually, causes\nthe imageblit to access an out-of-bound address value.\nTo solve this issue I made the resize_screen() be called\neven if the screen does not need any resizing, so it will\n'fix and fill' the fb_var_screeninfo independently.

See more information about CVE-2021-47383 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	6.6	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	Low
Integrity Impact:	Low	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (kernel)	ELSA-2024-7000	2024-09-24
Oracle Linux version 9 (kernel)	ELSA-2024-8617	2024-10-30