CVE-2024-43886 in Linux
Summary
by MITRE • 08/26/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Add null check in resource_log_pipe_topology_update
[WHY]
When switching from "Extend" to "Second Display Only" we sometimes call resource_get_otg_master_for_stream on a stream for the eDP, which is disconnected. This leads to a null pointer dereference.
[HOW]
Added a null check in dc_resource.c/resource_log_pipe_topology_update.
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Analysis
by VulDB Data Team • 09/29/2025
The vulnerability identified as CVE-2024-43886 represents a critical null pointer dereference issue within the Linux kernel's AMD display driver subsystem. This flaw specifically manifests in the drm/amd/display component where the resource_log_pipe_topology_update function fails to properly validate pointer references during display topology updates. The vulnerability occurs during dynamic display configuration changes when transitioning between different display modes, particularly when switching from an "Extend" configuration to a "Second Display Only" mode. The root cause stems from the driver's inability to handle disconnected eDP streams gracefully, leading to a scenario where resource_get_otg_master_for_stream is invoked on a null stream reference.
The technical implementation of this vulnerability involves the display resource management system within the AMD graphics driver where the dc_resource.c file contains the problematic function. When the system attempts to update pipe topology during display mode switching, it calls resource_get_otg_master_for_stream on an eDP stream that has already been disconnected or is in an invalid state. This results in a direct dereference of a null pointer, causing the kernel to crash or become unstable. The flaw demonstrates poor defensive programming practices and inadequate error handling within the graphics subsystem's resource management logic. The vulnerability is classified as a CWE-476 Null Pointer Dereference, which is a fundamental software security weakness that can lead to system crashes and potential privilege escalation.
The operational impact of this vulnerability extends beyond simple system instability to potentially compromise the entire display subsystem functionality. When triggered, the null pointer dereference can cause complete system hangs or kernel panics, making the affected system unusable until reboot. This is particularly concerning in server environments or embedded systems where display output is critical for system monitoring and management. The vulnerability affects systems running Linux kernels with AMD graphics drivers, particularly those implementing the display resource management functionality in the drm/amd/display subsystem. Attackers could potentially exploit this vulnerability to cause denial of service attacks against systems with AMD graphics hardware, though the direct security implications are limited to system availability rather than arbitrary code execution.
Mitigation strategies for CVE-2024-43886 focus on implementing proper null pointer validation within the affected driver code. The fix involves adding a straightforward null check in the resource_log_pipe_topology_update function within dc_resource.c to prevent the dereference of invalid stream pointers. System administrators should ensure their Linux kernels are updated to versions containing the patched driver code, which typically includes the null pointer validation that prevents the crash scenario. Organizations should prioritize patching systems running AMD graphics hardware, especially those in production environments where display stability is critical. The fix aligns with ATT&CK technique T1499.004 which involves system disruption through resource exhaustion or invalid pointer operations. Regular system updates and kernel patch management processes should be enforced to prevent similar vulnerabilities from persisting in the display subsystem, as this represents a common class of errors in kernel graphics drivers that require proper input validation and error handling mechanisms to prevent system instability.