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CVE-2021-47383

7.8 · HIGH
Published May 21, 2024 linux CWE-125 EPSS 0.27% (18th pctl)

Overview

CVE-2021-47383 is a high-severity vulnerability affecting linux linux_kernel. It was published on May 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical Description

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.

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status
linux linux_kernel >= 0, < 4.4.286 Affected

Frequently Asked Questions

What is CVE-2021-47383?

CVE-2021-47383 is a high-severity vulnerability affecting linux linux_kernel. It was published on May 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47383?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47383?

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47383?

CyberStrike's AI-powered security agents can automatically detect CVE-2021-47383 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.