Ubuntu update for xorg-server

1) Integer underflow

EUVDB-ID: #VU52197

Risk: Low

CVSSv4.0: 7.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/U:Clear]

CVE-ID: CVE-2021-3472

CWE-ID: CWE-191 - Integer underflow

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to integer underflow within the XChangeFeedbackControl() function. A local user can run a specially crafted program to trigger integer underflow and escalate privileges on the system.

Mitigation

Update the affected package xorg-server to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 20.10

xserver-xorg-core (Ubuntu package): before 2:1.18.4-0ubuntu0.12

xserver-xorg-core-hwe-18.04 (Ubuntu package): before 2:1.20.8-2ubuntu2.2~18.04.5

xserver-xorg-core-hwe-16.04 (Ubuntu package): before 2:1.19.6-1ubuntu4.1~16.04.6

CPE2.3

• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:20.10:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:xserver-xorg-core_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:o:canonical:xserver-xorg-core-hwe-18.04_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:o:canonical:xserver-xorg-core-hwe-16.04_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-4905-1

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.