CVE-2024-49898 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Check null-initialized variables
[WHAT & HOW]
drr_timing and subvp_pipe are initialized to null and they are not always assigned new values. It is necessary to check for null before dereferencing.
This fixes 2 FORWARD_NULL issues reported by Coverity.
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-49898 resides within the Linux kernel's AMD display driver subsystem, specifically within the direct rendering manager framework that handles display output management. This issue manifests as a forward null pointer dereference condition that occurs when the driver attempts to access memory locations through pointers that have not been properly initialized or assigned valid addresses. The flaw affects the display subsystem's handling of dynamic refresh rate timing and sub-video pipeline operations, which are critical components for modern display management in computing environments.
The technical root cause involves two variables drr_timing and subvp_pipe that are explicitly initialized to null values during the driver's initialization phase but are not guaranteed to receive valid assignments throughout the execution flow. These variables serve as pointers to display timing structures and video pipeline configurations respectively, and their null state creates a dangerous condition where subsequent code attempts to dereference them without proper validation. This pattern violates fundamental safe programming practices and creates opportunities for system crashes or potential exploitation scenarios when the driver processes display-related operations.
The operational impact of this vulnerability extends across multiple computing environments that utilize AMD graphics hardware, particularly affecting systems running recent Linux kernel versions where the display subsystem is actively engaged. When the driver encounters specific display configuration scenarios or transitions, the null pointer dereference can cause the kernel to crash, resulting in system instability, potential data loss, or complete system hang conditions. This vulnerability affects both desktop and server environments where AMD graphics are deployed, making it particularly concerning for enterprise computing infrastructure that relies on stable display management capabilities.
Security implications of this vulnerability align with CWE-476, which specifically addresses null pointer dereference conditions that can lead to denial of service or potentially more severe exploitation scenarios. The issue demonstrates characteristics consistent with ATT&CK technique T1499.001, which involves system network configuration modification through kernel-level vulnerabilities. The Coverity static analysis tool identified this as two separate forward null issues, indicating the vulnerability exists in multiple code paths within the display driver's control flow. Mitigation strategies include applying the kernel patch that implements proper null pointer validation before dereferencing the affected variables, ensuring that all code paths properly initialize or validate these critical pointers before use.
The fix for CVE-2024-49898 involves implementing defensive programming practices that check for null pointer conditions before attempting to access the memory locations referenced by drr_timing and subvp_pipe variables. This approach aligns with industry best practices for kernel development and follows established security guidelines for preventing common null pointer dereference vulnerabilities. The resolution demonstrates the importance of thorough code review processes and static analysis tools in identifying subtle but critical issues that can affect system stability and security. Organizations should prioritize applying this kernel update to maintain system integrity and prevent potential exploitation of this forward null pointer dereference vulnerability.