CVE-2021-4009: X.Org Server SProcXFixesCreatePointerBarrier Out-Of-Bounds Access Local Privilege Escalation Vulnerability
A flaw was found in xorg-x11-server in versions before 21.1.2 and before 1.20.14. An out-of-bounds access can occur in the SProcXFixesCreatePointerBarrier function. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Other sources
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 SProcXFixesCreatePointerBarrier 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.
— ZDI
Affected Software
Remediation
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the vulnerability ID for this vulnerability?
The vulnerability ID for this vulnerability is CVE-2021-4009.
What is the severity of CVE-2021-4009?
The severity of CVE-2021-4009 is high with a severity value of 7.8.
How does CVE-2021-4009 affect X.Org Server?
CVE-2021-4009 allows local attackers to escalate privileges on affected installations of X.Org Server.
How can CVE-2021-4009 be exploited?
An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit CVE-2021-4009.
What is the remedy for CVE-2021-4009?
The recommended remedy for CVE-2021-4009 depends on the version of X.Org Server being used, please refer to the official sources for specific remediation steps.