CVE-2024-49897 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Check phantom_stream before it is used
dcn32_enable_phantom_stream can return null, so returned value must be checked before used.
This fixes 1 NULL_RETURNS issue reported by Coverity.
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-49897 resides within the Linux kernel's graphics subsystem, specifically affecting the AMD display driver component under the drm/amd/display module. This issue represents a classic null pointer dereference scenario that could potentially lead to system instability or denial of service conditions. The vulnerability manifests in the dcn32_enable_phantom_stream function which is part of the display controller driver for AMD graphics hardware. The function is designed to manage phantom stream operations within the display controller, but fails to properly validate its return value before subsequent usage.
The technical flaw stems from insufficient input validation and error handling within the display driver code. When dcn32_enable_phantom_stream executes, it may legitimately return a null pointer under certain conditions such as resource exhaustion, hardware failure, or invalid parameter states. However, the calling code does not perform proper null checking before attempting to use this returned value, creating a scenario where a null pointer dereference could occur. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which is a fundamental programming error that can be exploited to crash systems or potentially execute arbitrary code.
The operational impact of this vulnerability extends beyond simple system crashes, as it affects the stability and reliability of graphics operations on systems utilizing AMD GPU hardware. When the null pointer dereference occurs, it can result in kernel panics, system hangs, or complete system crashes that require manual rebooting. This is particularly concerning in server environments or embedded systems where uninterrupted operation is critical. The vulnerability affects systems running Linux kernels with AMD display drivers, potentially impacting a wide range of devices from desktop computers to servers and embedded systems. The Coverity static analysis tool identified this as a NULL_RETURNS issue, highlighting the importance of proper error handling in kernel space code where such failures can have catastrophic consequences.
Mitigation strategies for this vulnerability require immediate kernel updates from vendors who have patched the issue, as well as implementing proper input validation and error handling procedures. System administrators should prioritize applying the relevant kernel security patches that address this specific null pointer dereference. Additionally, monitoring systems should be configured to detect unusual system behavior that might indicate kernel crashes or instability related to graphics operations. The fix involves adding proper null checks before using the return value from dcn32_enable_phantom_stream, ensuring that the code gracefully handles cases where the function fails to allocate or initialize the required resources. This aligns with ATT&CK technique T1547.001 for privilege escalation through kernel exploits, though the immediate impact is more focused on system stability rather than direct privilege elevation. Organizations should also consider implementing additional monitoring and alerting mechanisms to detect potential exploitation attempts or system instability related to graphics driver operations.