CVE-2021-47383

High

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.

Package Linux Kernel
Published 2024-05-21
Last modified 2025-12-10
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.1

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Weakness type

CWE-125

CVE-2021-47383 is a Out-of-bounds Read vulnerability

What is Out-of-bounds Read?

The product reads data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.12 and later are affected. Fixed in 4.4.286, 4.9.285, 4.14.249, 4.19.209, 5.4.151, 5.10.71, 5.14.10, 5.15 and their respective stable series.

Affected from
≥ 2.6.12
Fixed in
✓ 4.4.286 4.4.x ✓ 4.9.285 4.9.x ✓ 4.14.249 4.14.x ✓ 4.19.209 4.19.x ✓ 5.4.151 5.4.x ✓ 5.10.71 5.10.x ✓ 5.14.10 5.14.x ✓ 5.15

References

8 total
Showing 5 of 8 references View all on NVD

Frequently asked questions

  • What is CVE-2021-47383?

    CVE-2021-47383 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . It affects Linux kernel versions from 2.6.12 onward and has been patched in 4.4.286, 4.9.285, 4.14.249 and others. CVE-2021-47383 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2021-47383?

    CVE-2021-47383 has a CVSS score of 7.1 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H .

  • Is there a patch available for CVE-2021-47383?

    Yes. CVE-2021-47383 has been patched. Fixed versions include 4.4.286, 4.9.285, 4.14.249 and others. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2021-47383 actively exploited?

    No. CVE-2021-47383 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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