CVE-2024-26719 in Linux
Summary
by MITRE • 04/03/2024
In the Linux kernel, the following vulnerability has been resolved:
nouveau: offload fence uevents work to workqueue
This should break the deadlock between the fctx lock and the irq lock.
This offloads the processing off the work from the irq into a workqueue.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 08/03/2025
The vulnerability identified as CVE-2024-26719 affects the Linux kernel's nouveau graphics driver implementation and represents a critical deadlock condition that can compromise system stability and availability. This issue specifically manifests within the graphics subsystem where the nouveau driver manages nvidia graphics hardware through the open-source nouveau kernel module. The flaw occurs during the processing of fence uevents which are used to coordinate synchronization between graphics operations and kernel subsystems. The vulnerability arises from the driver's improper handling of interrupt contexts where work processing directly occurs within interrupt service routines rather than being deferred to appropriate kernel workqueues.
The technical implementation of this vulnerability stems from the nouveau driver's failure to properly separate interrupt context processing from kernel workqueue execution. When fence uevents are generated during graphics operations, the driver attempts to process these events directly within interrupt handlers which creates a dangerous lock ordering dependency. The fctx lock and irq lock dependencies create a circular wait condition where the interrupt handler cannot complete its processing while holding one lock, yet requires the other lock to proceed with the work. This classic deadlock scenario can cause the entire graphics subsystem to hang, potentially leading to complete system lockup or requiring manual intervention to recover from the frozen state.
The operational impact of CVE-2024-26719 extends beyond simple system instability as it represents a potential denial-of-service vulnerability that can affect systems running graphics-intensive workloads. Systems utilizing nvidia graphics hardware through the nouveau driver are particularly at risk, including servers, desktop computers, and embedded systems that rely on graphics processing. The deadlock condition can manifest during normal graphics operations such as video rendering, 3d graphics acceleration, or any scenario involving concurrent graphics operations that generate fence uevents. This vulnerability aligns with CWE-362, which describes race conditions and deadlock conditions in concurrent programming, and demonstrates the critical importance of proper lock ordering and context separation in kernel drivers. The issue also relates to ATT&CK technique T1490, which covers resource hijacking through denial-of-service attacks, as the vulnerability can be exploited to cause system instability and availability issues.
The resolution for CVE-2024-26719 implements a fundamental architectural change by offloading fence uevent processing from interrupt contexts to dedicated kernel workqueues. This approach follows established kernel development practices for handling interrupt-driven work that requires significant processing time or may block on other resources. By moving the work processing to a workqueue, the driver eliminates the direct dependency between interrupt handlers and the fctx lock, thereby breaking the deadlock condition. The fix ensures that interrupt contexts remain lightweight and responsive while complex processing occurs in the appropriate kernel execution context. This mitigation strategy aligns with kernel security best practices and addresses the fundamental design flaw that allowed the circular dependency between locks to occur. The implementation follows standard kernel patterns for interrupt handling and workqueue management, reducing the attack surface while maintaining system performance and stability.
The vulnerability represents a significant concern for system administrators and security professionals managing Linux systems with graphics capabilities, particularly in enterprise environments where system uptime and reliability are critical. The fix demonstrates the importance of proper kernel driver design and the dangers of mixing interrupt contexts with complex synchronization primitives. Organizations should prioritize updating their systems to address this vulnerability, as it can lead to unexpected system crashes and potential denial-of-service conditions that may affect user productivity and system availability. The resolution also highlights the ongoing challenges in kernel security where seemingly minor architectural decisions can lead to critical system stability issues, emphasizing the need for comprehensive testing and review of kernel subsystems that handle hardware interaction and concurrent processing.