CVE-2024-49907 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Check null pointers before using dc->clk_mgr
[WHY & HOW]
dc->clk_mgr is null checked previously in the same function, indicating it might be null.
Passing "dc" to "dc->hwss.apply_idle_power_optimizations", which dereferences null "dc->clk_mgr". (The function pointer resolves to "dcn35_apply_idle_power_optimizations".)
This fixes 1 FORWARD_NULL issue reported by Coverity.
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Analysis
by VulDB Data Team • 03/04/2026
The vulnerability identified as CVE-2024-49907 represents a critical null pointer dereference flaw within the Linux kernel's AMD display subsystem, specifically affecting the display component driver. This issue manifests in the drm/amd/display subsystem where the kernel fails to properly validate pointer references before dereferencing them, creating a potential pathway for system instability or exploitation. The vulnerability occurs during the execution of idle power optimization routines, where the kernel attempts to access a clock manager structure that may not have been properly initialized or allocated.
The technical flaw stems from improper null pointer validation within the display controller hardware security subsystem. The kernel function responsible for applying idle power optimizations receives a display controller context pointer that contains a null reference to the clock manager component. This situation arises because while the code previously implemented null checks for dc->clk_mgr within the same function, these checks occur at different execution points, leaving a window where the pointer could be null when passed to the hwss.apply_idle_power_optimizations function. The function pointer resolution leads to dcn35_apply_idle_power_optimizations execution, which then attempts to dereference the null clock manager pointer, resulting in a system crash or undefined behavior.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling denial of service attacks against systems running affected Linux kernel versions. When the null pointer dereference occurs during power management operations, it can cause the entire display subsystem to become unresponsive, rendering graphical interfaces inaccessible and potentially affecting system stability. This vulnerability affects systems utilizing AMD graphics hardware with the display controller driver, particularly those implementing the dcn35 hardware support. The issue represents a FORWARD_NULL type flaw according to Coverity static analysis, indicating that a pointer flows from a source to a destination without proper null validation, which is classified under CWE-476 as "NULL Pointer Dereference" and can be mapped to ATT&CK technique T1490 for system destruction through resource exhaustion or component failure.
Mitigation strategies for CVE-2024-49907 require immediate kernel updates from vendors who have patched this specific null pointer dereference issue. System administrators should prioritize applying the latest kernel security patches that include the fix for this display subsystem vulnerability. The patch implements proper null pointer validation before passing the dc->clk_mgr pointer to the hardware security subsystem functions, ensuring that the clock manager reference is properly initialized before any dereference operations occur. Organizations should also consider implementing monitoring solutions to detect potential exploitation attempts targeting this specific vulnerability, particularly in environments where display subsystem stability is critical. Additionally, maintaining up-to-date kernel versions and following security best practices for kernel patch management will prevent similar issues from arising in other display driver components, as this vulnerability demonstrates the importance of proper null pointer validation in kernel space code execution.