CVE-2021-4008: X.Org Server SProcRenderCompositeGlyphs Out-Of-Bounds Access 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 SProcRenderCompositeGlyphs 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 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.
— ZDI
Affected Software
Remediation
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is CVE-2021-4008?
CVE-2021-4008 is a vulnerability that allows local attackers to escalate privileges on affected installations of X.Org Server.
How can this vulnerability be exploited?
To exploit CVE-2021-4008, an attacker must first obtain the ability to execute low-privileged code on the target system.
What is the severity of CVE-2021-4008?
The severity of CVE-2021-4008 is high, with a CVSS score of 7.8.
How do I fix CVE-2021-4008?
To fix CVE-2021-4008, update X.Org Server to version 2:1.20.13-1ubuntu1.1 or later.
Where can I find more information about CVE-2021-4008?
You can find more information about CVE-2021-4008 at the following references: [Reference 1](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PDHYZM6FII35JA7J275MFCJO6ADJUPQX/) [Reference 2](https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/T57DCF726O5LLTST4NBL5PQ7DLPB46HT/) [Reference 3](https://lists.x.org/archives/xorg-announce/2021-December/003122.html)