What is the severity of ZDI-21-1547?

ZDI-21-1547 has been classified as a high severity vulnerability.

How do I fix ZDI-21-1547?

To fix ZDI-21-1547, update to the latest version of X.Org Server that addresses this vulnerability.

What type of attack does ZDI-21-1547 involve?

ZDI-21-1547 involves a local privilege escalation attack that requires low-privileged code execution.

Which versions of X.Org Server are affected by ZDI-21-1547?

ZDI-21-1547 affects certain installations of X.Org Server that have not been patched against this vulnerability.

What can attackers achieve by exploiting ZDI-21-1547?

By exploiting ZDI-21-1547, attackers can escalate their privileges on the affected system.

Vulnerability/
ZDI-21-1547

high

7.8

29/1/2025

ZDI-21-1547: X.Org Server SProcRenderCompositeGlyphs Out-Of-Bounds Access Privilege Escalation Vulnerability

This vulnerability allows local attackers to escalate privileges on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the handling of SProcRenderCompositeGlyphs requests. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root.

Affected Software	Affected Version	How to fix
X.Org Xserver

Never miss a vulnerability like this again

Reference Links

Frequently Asked Questions

What is the severity of ZDI-21-1547?
ZDI-21-1547 has been classified as a high severity vulnerability.
How do I fix ZDI-21-1547?
To fix ZDI-21-1547, update to the latest version of X.Org Server that addresses this vulnerability.
What type of attack does ZDI-21-1547 involve?
ZDI-21-1547 involves a local privilege escalation attack that requires low-privileged code execution.
Which versions of X.Org Server are affected by ZDI-21-1547?
ZDI-21-1547 affects certain installations of X.Org Server that have not been patched against this vulnerability.
What can attackers achieve by exploiting ZDI-21-1547?
By exploiting ZDI-21-1547, attackers can escalate their privileges on the affected system.

agent/references
agent/type
agent/title
agent/severity
agent/softwarecombine
agent/description
agent/event
agent/source
agent/tags
collector/zdi-advisory
source/ZDI
alias/ZDI-21-1547
alias/ZDI-CAN-14192
alias/CVE-2021-4008
agent/software-canonical-lookup
agent/software-canonical-lookup-request
vendor/x.org
canonical/x.org xserver

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co

By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.

Frequently Asked Questions

What is the severity of ZDI-21-1547?
ZDI-21-1547 has been classified as a high severity vulnerability.
How do I fix ZDI-21-1547?
To fix ZDI-21-1547, update to the latest version of X.Org Server that addresses this vulnerability.
What type of attack does ZDI-21-1547 involve?
ZDI-21-1547 involves a local privilege escalation attack that requires low-privileged code execution.
Which versions of X.Org Server are affected by ZDI-21-1547?
ZDI-21-1547 affects certain installations of X.Org Server that have not been patched against this vulnerability.
What can attackers achieve by exploiting ZDI-21-1547?
By exploiting ZDI-21-1547, attackers can escalate their privileges on the affected system.