CVE-2022-2320 in X11
Summary
by MITRE • 09/02/2022
A flaw was found in the Xorg-x11-server. The specific flaw exists within the handling of ProcXkbSetDeviceInfo 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. This flaw allows an attacker to escalate privileges and execute arbitrary code in the context of root.
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Analysis
by VulDB Data Team • 08/29/2025
The vulnerability identified as CVE-2022-2320 resides within the Xorg-x11-server component of Linux systems, representing a critical security flaw that has significant implications for system integrity and privilege escalation. This vulnerability specifically manifests in the processing of ProcXkbSetDeviceInfo requests, which are part of the X Keyboard Extension protocol used for managing keyboard devices within X Window System environments. The Xorg-x11-server serves as the core component responsible for handling graphical user interfaces and input device management, making it a prime target for attackers seeking to gain elevated system privileges.
The technical root cause of this vulnerability stems from insufficient validation of user-supplied data within the ProcXkbSetDeviceInfo request handling mechanism. When the server processes these requests, it fails to properly validate the length and content of incoming data structures, particularly those related to keyboard device information. This inadequate input validation creates a buffer overflow condition where maliciously crafted data can cause the application to write beyond the boundaries of allocated memory buffers. The flaw operates at the memory management level where the server's handling of keyboard device configuration parameters lacks proper bounds checking, allowing attackers to manipulate memory layout through carefully constructed input sequences.
The operational impact of this vulnerability extends far beyond simple memory corruption, as it provides attackers with the capability to escalate privileges and execute arbitrary code with root-level permissions. This privilege escalation occurs because the Xorg-x11-server typically runs with elevated privileges to manage hardware resources and system-level input devices, making it a valuable target for attackers seeking persistent system control. When an attacker successfully exploits this buffer overflow, they can potentially overwrite critical memory locations including return addresses, function pointers, or other control structures that govern program execution flow. The resulting code execution occurs within the privileged context of the X server process, effectively granting the attacker complete control over the affected system.
The security implications of CVE-2022-2320 align with CWE-121, which describes heap-based buffer overflow conditions, and can be mapped to ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation'. The vulnerability represents a classic example of how input validation failures in system-level components can lead to complete system compromise, particularly in environments where X11 servers are actively running and accessible to unprivileged users. This flaw demonstrates the critical importance of proper memory management and input validation in server applications, as it allows attackers to leverage seemingly benign keyboard configuration requests to achieve root access.
Mitigation strategies for this vulnerability should focus on immediate patch application from upstream vendors, as the flaw requires direct code modifications to address the insufficient input validation. System administrators should implement network segmentation to limit access to X11 servers where possible, and consider disabling unnecessary X11 forwarding capabilities in remote access scenarios. Additionally, monitoring for unusual X11 server activity and implementing proper access controls can help detect potential exploitation attempts. The vulnerability also highlights the importance of security testing for protocol implementations, particularly those handling user-supplied data in privileged contexts, and underscores the need for comprehensive input validation across all system components that process external data streams.