CVE-2023-5367 in X11 Server
Summary
by MITRE • 10/25/2023
A out-of-bounds write flaw was found in the xorg-x11-server. This issue occurs due to an incorrect calculation of a buffer offset when copying data stored in the heap in the XIChangeDeviceProperty function in Xi/xiproperty.c and in RRChangeOutputProperty function in randr/rrproperty.c, allowing for possible escalation of privileges or denial of service.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/09/2025
The vulnerability identified as CVE-2023-5367 represents a critical out-of-bounds write flaw within the xorg-x11-server component of the X Window System, a fundamental graphics subsystem in Unix-like operating systems. This flaw exists in the core X server implementation where buffer offset calculations fail to properly validate input parameters during property manipulation operations. The vulnerability specifically manifests in two key functions: XIChangeDeviceProperty within the Xi/xiproperty.c module and RRChangeOutputProperty within the randr/rrproperty.c module, both of which handle device and display property management respectively. The flaw stems from inadequate bounds checking when copying data from heap-allocated memory regions, creating a scenario where malicious input could trigger memory corruption beyond intended buffer boundaries.
The technical nature of this vulnerability places it squarely within CWE-787, which defines out-of-bounds write conditions that occur when a program writes to memory locations outside the bounds of a buffer. The flaw operates at the intersection of memory management and input validation, where the X server fails to properly calculate buffer offsets when processing device or display property changes. Attackers can exploit this by crafting malicious property data that, when processed through either of these functions, causes the server to write beyond allocated memory boundaries. This memory corruption can manifest in various ways depending on the execution context, potentially leading to privilege escalation through controlled memory overwrite attacks or denial of service via system crashes.
The operational impact of CVE-2023-5367 extends beyond simple system instability to encompass potential privilege escalation capabilities that could allow attackers to gain elevated system privileges. When exploited, the vulnerability can cause the X server to crash and restart, leading to denial of service for graphical applications and desktop environments. More concerning is the potential for privilege escalation, where an attacker with access to the X server could manipulate memory layout to execute arbitrary code with higher privileges. The vulnerability affects systems running xorg-x11-server versions that include the affected code paths, particularly impacting desktop environments and systems that rely on X11 for graphical user interfaces. The attack surface includes any application or user interaction that triggers property change operations through the X server's interface, making this a widespread concern across Linux desktop and server environments.
Mitigation strategies for CVE-2023-5367 should prioritize immediate patching of affected xorg-x11-server installations, as provided by upstream vendors and distribution maintainers. System administrators should implement monitoring for abnormal X server behavior and memory allocation patterns that could indicate exploitation attempts. The vulnerability's nature suggests that defensive programming techniques including bounds checking, stack canaries, and address space layout randomization should be enabled system-wide to reduce exploit reliability. Additionally, implementing network segmentation and access controls to limit X server exposure can reduce attack surface, while regular security audits of X server configurations can help identify potential misuse vectors. Organizations should also consider implementing intrusion detection systems that monitor for anomalous property change operations that might indicate exploitation attempts, as these functions are frequently targeted in privilege escalation attacks. The flaw's classification under ATT&CK technique T1068, which covers privilege escalation through local system services, indicates that exploitation attempts would likely be detected by endpoint protection systems that monitor for suspicious process behaviors and memory access patterns.