CVE-2020-28915: Medium severity linux kernel vulnerability

Published Nov 16, 2020
·
Updated

A buffer over-read (at the framebuffer layer) in the fbcon code in the Linux kernel before 5.8.15 could be used by local attackers to read kernel memory, aka CID-6735b4632def.

Other sources

An out-of-bounds (OOB) memory access flaw was found in fbcongetfont() in drivers/video/fbdev/core/fbcon.c in fbcon driver module in the Linux kernel. A bound check failure allows a local attacker with special user privilege to gain access to out-of-bounds memory, leading to a system crash or a leak of internal kernel information. The highest threat from this vulnerability is to integrity and system availability.

An out-of-bounds (OOB) memory access flaw was found in fbcongetfont() in drivers/video/fbdev/core/fbcon.c in fbcon driver module in the Linux kernel. A bound check failure may allow a local attacker with special user privilege to gain access to out-of-bounds memory leading to a system crash or a leak of internal kernel information. The highest threat from this vulnerability is to system availability.

Reference: https://syzkaller.appspot.com/bug?id=08b8be45afea11888776f897895aef9ad1c3ecfd

Red Hat

Affected Software

4 affected componentsFixes available
redhat/kernel-rt<0:4.18.0-372.13.1.rt7.170.el8_6
0:4.18.0-372.13.1.rt7.170.el8_6
redhat/kernel<0:4.18.0-372.13.1.el8_6
0:4.18.0-372.13.1.el8_6
Linux Linux kernel<5.8.15
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.22-16.12.25-1

Remediation

Information

Add 'nomodeset' option as kernel boot parameter to disable frame buffering (edit /etc/default/grub, and run 'grub2-mkconfig -o /boot/grub2/grub.cfg' and reboot). ~~~ # cat /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-147.el8.x86_64 root=/dev/mapper/rhel_rhel8u2--1-root ro crashkernel=auto resume=/dev/mapper/rhel_rhel8u2--1-swap rd.lvm.lv=rhel_rhel8u2-1/root rd.lvm.lv=rhel_rhel8u2-1/swap nomodeset # ls -l /dev/fb* ls: cannot access '/dev/fb*': No such file or directory ~~~

Event History

Nov 16, 2020
CVE Published
12:00 AM
Nov 18, 2020
CVE Published
via MITRE·07:59 AM
Data Sourced
via MITRE·07:59 AM
Description
Data Sourced
via Red Hat·04:43 PM
DescriptionSeverityAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·11:48 PM
Description
May 2, 2025
Data Sourced
via Ubuntu·04:25 AM
RemedyDescriptionSeverityAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2020-28915?

CVE-2020-28915 is classified as a medium severity vulnerability due to its potential for local exploitation to read kernel memory.

2

How do I fix CVE-2020-28915?

To remediate CVE-2020-28915, upgrade to kernel versions 5.10.223-1, 5.10.226-1, or any later versions listed in the advisory.

3

What kind of vulnerability is CVE-2020-28915?

CVE-2020-28915 is a buffer over-read vulnerability that occurs at the framebuffer layer in the Linux kernel.

4

Which Linux kernel versions are affected by CVE-2020-28915?

CVE-2020-28915 affects Linux kernel versions prior to 5.8.15.

5

Can CVE-2020-28915 be exploited remotely?

CVE-2020-28915 cannot be exploited remotely, as it requires local access to the system.

Contact

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