CVE-2019-16230 in Linux
Summary
by MITRE
drivers/gpu/drm/radeon/radeon_display.c in the Linux kernel 5.2.14 does not check the alloc_workqueue return value, leading to a NULL pointer dereference. NOTE: A third-party software maintainer states that the work queue allocation is happening during device initialization, which for a graphics card occurs during boot. It is not attacker controllable and OOM at that time is highly unlikely
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability identified as CVE-2019-16230 resides within the Linux kernel's Radeon graphics driver implementation, specifically in the radeon_display.c file version 5.2.14. This flaw represents a classic null pointer dereference issue that occurs when the kernel fails to validate the return value from the alloc_workqueue function call. The Radeon graphics driver component is responsible for managing display outputs and graphics processing tasks on AMD Radeon hardware, making it a critical subsystem within the kernel's graphics stack. When the alloc_workqueue function fails to allocate the requested workqueue structure, it returns a NULL pointer, but the driver code does not perform this validation check before proceeding with subsequent operations that assume a valid workqueue structure exists.
The technical execution of this vulnerability occurs during the initialization or operation of display-related functions within the Radeon driver where workqueues are essential for asynchronous task execution. When alloc_workqueue fails, the driver continues processing without proper error handling, leading to a situation where subsequent code attempts to dereference the NULL pointer returned by the failed allocation. This results in an immediate kernel panic or system crash, effectively causing a denial of service condition that renders the affected system unstable or unusable. The flaw demonstrates poor defensive programming practices and highlights the importance of proper error handling in kernel space code where resource allocation failures can have catastrophic consequences. This vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference issues, and it aligns with ATT&CK technique T1499.004 which involves network disruption through system resource exhaustion or kernel-level crashes.
The operational impact of CVE-2019-16230 extends beyond simple system instability to potentially affect any system running the affected Linux kernel version with Radeon graphics hardware. Systems utilizing this graphics driver for display output, including servers, desktops, and embedded devices, become vulnerable to uncontrolled crashes that can occur during normal operation or under specific workload conditions. The vulnerability is particularly concerning in enterprise environments where system reliability is paramount, as a single kernel crash can result in service interruption and data loss. Attackers who can trigger the specific conditions leading to this null pointer dereference could potentially cause persistent system instability or use this as a vector for more sophisticated attacks targeting the kernel's memory management subsystem. The exploitation requires conditions that cause alloc_workqueue to fail, which may occur under resource-constrained conditions or when the system attempts to allocate workqueues beyond available limits, making this vulnerability a potential target for resource exhaustion attacks that could be amplified through kernel-level denial of service mechanisms.
Mitigation strategies for CVE-2019-16230 primarily involve upgrading to a patched kernel version where proper error handling has been implemented for the alloc_workqueue return value. System administrators should prioritize applying the relevant kernel security patches from their distribution vendors or directly from the Linux kernel source repository. Additionally, monitoring systems should be configured to detect kernel panics or crashes that may indicate exploitation attempts, as these events often precede or accompany the successful triggering of this vulnerability. The fix typically involves adding a simple null pointer check after the alloc_workqueue call, ensuring that the driver properly handles allocation failures by either aborting the operation gracefully or falling back to alternative implementation strategies. Organizations should also consider implementing kernel hardening measures such as stack canaries, kernel address space layout randomization, and other mitigations that can make exploitation more difficult even if the underlying vulnerability remains unpatched. Regular kernel updates and security assessments should be part of the operational security posture to prevent similar issues from arising in other kernel subsystems, as this vulnerability demonstrates the critical importance of comprehensive error handling in kernel space code where resource allocation failures can lead to system-wide instability.