CVE-2024-49893 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Check stream_status before it is used
[WHAT & HOW]
dc_state_get_stream_status can return null, and therefore null must be checked before stream_status is 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-2024-49893 resides within the Linux kernel's display subsystem, specifically affecting the AMD display driver component known as drm/amd/display. 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 dc_state_get_stream_status function which is responsible for retrieving stream status information within the display controller state management system.
The technical flaw stems from insufficient validation of return values within the display driver code. When dc_state_get_stream_status is invoked, it may return a null pointer under certain conditions, particularly when stream status information cannot be properly retrieved or when the display state is in an inconsistent condition. The code path that follows this function call fails to perform a null check before attempting to dereference the returned stream_status pointer, creating a scenario where the system attempts to access memory at a null address.
This vulnerability directly relates to CWE-476 which defines NULL Pointer Dereference as a condition where a null value is used as a pointer reference, leading to program crashes or potential exploitation. The issue was identified through static analysis tools and specifically flagged by Coverity as a NULL_RETURNS problem, indicating that the code does not properly handle cases where functions may return null values. The operational impact of this vulnerability extends beyond simple system crashes, as it could potentially be exploited to cause denial of service conditions or in more sophisticated attack scenarios, though the immediate risk appears to be primarily system instability rather than arbitrary code execution.
The fix implemented addresses this issue by introducing a proper null check before the stream_status pointer is used in subsequent operations. This defensive programming approach ensures that the driver gracefully handles cases where stream status information cannot be retrieved, preventing the null pointer dereference that would otherwise occur. The mitigation strategy aligns with the principle of input validation and proper error handling that is fundamental to secure software development practices. System administrators should prioritize applying this kernel update as it resolves a potential stability issue that could affect systems running AMD graphics hardware, particularly those utilizing the display manager functionality. The fix demonstrates the importance of comprehensive error handling in kernel space code where such vulnerabilities can have significant impact on system reliability and security posture.