CVE-2023-54263 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/kms/nv50-: init hpd_irq_lock for PIOR DP
Fixes OOPS on boards with ANX9805 DP encoders.
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Analysis
by VulDB Data Team • 06/08/2026
The vulnerability identified as CVE-2023-54263 represents a critical initialization flaw within the Linux kernel's display subsystem, specifically affecting the nouveau graphics driver implementation. This issue manifests in the drm/nouveau/kms/nv50- subsystem where the hpd_irq_lock variable fails to be properly initialized for PIOR DP (Display Port) configurations. The root cause stems from inadequate locking mechanism setup during the hardware initialization phase of display port interfaces, particularly impacting systems utilizing ANX9805 DP encoders. The failure to initialize this crucial lock structure creates a scenario where concurrent access attempts to hardware resources can result in kernel oops conditions and system instability. This vulnerability directly impacts the reliability and stability of graphics operations in Linux environments where nouveau drivers are employed for display management. The flaw represents a classic race condition scenario where shared resources are accessed without proper synchronization primitives, leading to unpredictable system behavior and potential denial of service conditions. According to CWE classification, this vulnerability maps to CWE-362, Concurrent Execution using Shared Resource with Improper Synchronization, which is a well-documented pattern of race condition vulnerabilities in kernel space programming. The specific context of this issue involves the nouveau driver's handling of hotplug detection interrupts for display port interfaces, where proper lock initialization is essential for maintaining system stability during dynamic display configuration changes. The operational impact extends beyond simple system crashes to potentially affect user experience during display port hotplug events, where the system may become unresponsive or require manual intervention to restore normal graphics functionality.
The technical implementation of this vulnerability lies in the missing initialization of the hpd_irq_lock variable within the PIOR DP initialization path of the nouveau driver's kernel module. This lock mechanism is essential for protecting shared data structures and hardware registers that manage hotplug detection interrupts for display port connections. When the ANX9805 DP encoder is present on a system, the driver attempts to process hotplug events without proper lock protection, leading to kernel oops conditions that manifest as system panics or unexpected reboots. The missing initialization creates a scenario where multiple threads or interrupt handlers may attempt to access the same hardware resources simultaneously, resulting in memory corruption and system instability. This type of vulnerability falls under the ATT&CK framework's T1059.003 technique category, specifically targeting kernel-level execution environments where privilege escalation opportunities exist. The flaw demonstrates poor defensive programming practices where synchronization primitives are not properly established during initialization phases, creating a window of opportunity for race conditions to occur. The vulnerability is particularly insidious because it only manifests under specific hardware configurations involving ANX9805 encoders, making it difficult to detect during standard testing procedures and potentially allowing it to persist in production environments without immediate detection.
Mitigation strategies for CVE-2023-54263 require immediate application of the kernel patch that properly initializes the hpd_irq_lock variable for PIOR DP configurations. System administrators should prioritize updating their Linux kernel installations to versions that include the fix, particularly those running nouveau drivers with display port hardware. The recommended approach involves implementing a comprehensive kernel update strategy that includes testing in staging environments before deployment to production systems. Organizations utilizing embedded systems or specialized hardware configurations should conduct thorough regression testing to ensure that the fix does not introduce compatibility issues with existing display port setups. Additional monitoring should be implemented to track system stability metrics and detect any residual issues following the patch application. The fix addresses the core synchronization problem by ensuring proper lock initialization during driver setup, preventing concurrent access violations that previously led to kernel oops conditions. Security teams should also consider implementing hardware-specific monitoring for systems with ANX9805 encoders, as these devices represent the primary attack surface for this vulnerability. Regular vulnerability assessments should include checks for proper initialization of kernel synchronization primitives, particularly in graphics and display subsystems where race conditions can have severe operational impacts. The resolution of this vulnerability aligns with industry best practices for kernel security hardening and demonstrates the importance of proper resource initialization in multi-threaded kernel environments. Organizations should also review their display port hardware configurations and maintain updated inventories of devices that may be susceptible to similar initialization flaws in other driver components.