CVE-2023-6478 in X11 Server
Summary
by MITRE • 12/13/2023
A flaw was found in xorg-server. A specially crafted request to RRChangeProviderProperty or RRChangeOutputProperty can trigger an integer overflow which may lead to a disclosure of sensitive information.
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Analysis
by VulDB Data Team • 07/09/2025
The vulnerability identified as CVE-2023-6478 resides within the xorg-server component of the X Window System, a critical subsystem responsible for managing graphical user interfaces on Unix-like operating systems. This flaw manifests as an integer overflow condition that occurs when processing specific requests related to display properties through the RRChangeProviderProperty or RRChangeOutputProperty functions. The xorg-server serves as the foundation for graphical operations across numerous Linux distributions and Unix-based systems, making this vulnerability particularly concerning for widespread impact.
The technical implementation of this vulnerability stems from inadequate input validation within the property handling mechanisms of the X server. When maliciously crafted requests are sent to the RRChangeProviderProperty or RRChangeOutputProperty functions, the server fails to properly validate the size parameters of the property data being processed. This oversight allows an attacker to manipulate the integer arithmetic operations that determine memory allocation or buffer boundaries, resulting in an integer overflow condition. The overflow can cause subsequent memory operations to access unauthorized memory regions, potentially leading to information disclosure through the exposure of sensitive data from adjacent memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a potential pathway for more sophisticated attacks within the graphical subsystem. An attacker who can successfully exploit this integer overflow could potentially gain access to sensitive information such as cryptographic keys, session tokens, or other confidential data stored in memory regions adjacent to the affected buffers. This vulnerability is particularly dangerous in environments where the X server runs with elevated privileges or where graphical interfaces are used to access sensitive applications. The flaw can be exploited remotely through network-based X11 connections or locally through crafted applications that interact with the X server.
From a cybersecurity perspective, this vulnerability maps to CWE-190, which specifically addresses integer overflow conditions, and aligns with ATT&CK technique T1059.007 for executing malicious code through the X11 protocol. The vulnerability demonstrates the ongoing challenges in securing graphical subsystems where complex protocols interact with privileged processes, creating potential attack surfaces that can be leveraged for information disclosure attacks. Organizations running systems with xorg-server components should prioritize patching this vulnerability as it represents a significant risk to system confidentiality and could serve as a stepping stone for more advanced exploitation techniques. The remediation approach typically involves updating to patched versions of xorg-server where proper input validation and integer overflow protections have been implemented to prevent malicious requests from triggering the vulnerable code paths.
This vulnerability highlights the critical importance of robust input validation in server-side applications, particularly those handling untrusted data from network connections. The integer overflow condition represents a classic security flaw that can be exploited to bypass memory safety mechanisms and access sensitive information. Proper bounds checking and integer overflow protection mechanisms should be implemented throughout the X server's property handling functions to prevent similar issues from occurring in future releases. The impact of this vulnerability underscores the necessity for continuous security assessment of core system components that operate with elevated privileges and handle data from potentially malicious sources.