#VU53336 Input validation error in libx11 - CVE-2021-31535

Vulnerability identifier: #VU53336

Vulnerability risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-31535

CWE-ID: CWE-20

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
libx11
Other software / Other software solutions

Vendor: xorg.freedesktop.org

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of color names within the XLookupColor() function. A local user can run a specially crafted application on the system and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

libx11: 1.0.99.1 - 1.7.0

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External links
https://seclists.org/oss-sec/2021/q2/153
https://unparalleled.eu/blog/2021/20210518-using-xterm-to-navigate-the-huge-color-space/

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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. However, proof of concept for this vulnerability is available.