CVE-2024-49923 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Pass non-null to dcn20_validate_apply_pipe_split_flags
[WHAT & HOW]
"dcn20_validate_apply_pipe_split_flags" dereferences merge, and thus it cannot be a null pointer. Let's pass a valid pointer to avoid null dereference.
This fixes 2 FORWARD_NULL issues reported by Coverity.
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Analysis
by VulDB Data Team • 03/05/2026
The vulnerability identified as CVE-2024-49923 resides within the Linux kernel's graphics subsystem, specifically affecting the AMD display driver component known as drm/amd/display. This issue manifests as a potential null pointer dereference that could compromise system stability and security. The flaw occurs within the dcn20_validate_apply_pipe_split_flags function which is part of the display controller driver responsible for managing display pipe splitting operations in AMD graphics hardware. The vulnerability represents a critical reliability concern that could lead to system crashes or denial of service conditions when the driver processes certain display configuration scenarios.
The technical root cause of this vulnerability stems from improper parameter validation within the dcn20_validate_apply_pipe_split_flags function implementation. The function attempts to dereference a pointer named merge without ensuring that it contains a valid memory address. According to CWE-476, this constitutes a null pointer dereference vulnerability where the code assumes a pointer will always contain a valid reference. The function signature requires a non-null pointer to be passed, yet the calling code fails to verify this precondition before passing the argument. This specific issue was identified through static analysis tools like Coverity, which flagged two instances of FORWARD_NULL conditions where pointers are used without null checks. The vulnerability operates at the kernel level where invalid memory access can lead to system instability and potential privilege escalation opportunities.
The operational impact of CVE-2024-49923 extends beyond simple system crashes to encompass broader security implications within the Linux kernel environment. When the display driver encounters conditions that trigger this code path, the system may experience unexpected termination or kernel panic conditions that prevent normal operation of graphical interfaces. This vulnerability affects systems utilizing AMD graphics hardware with display controller version 2.0, potentially impacting desktop environments, servers with graphical interfaces, and embedded systems that rely on AMD GPU functionality. The null pointer dereference could be exploited by malicious actors to cause denial of service attacks against systems or potentially gain unauthorized access to kernel memory spaces. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Endpoint Denial of Service) and could potentially enable privilege escalation through kernel memory corruption.
Mitigation strategies for CVE-2024-49923 involve immediate kernel updates from the Linux kernel maintainers, which should include the fix that ensures proper validation of the merge pointer before function invocation. System administrators should prioritize patching affected systems, particularly those running kernel versions that include the vulnerable drm/amd/display driver code. The fix implements a straightforward validation mechanism that ensures the merge parameter passed to dcn20_validate_apply_pipe_split_flags contains a valid memory reference before any dereference operations occur. Organizations should also implement monitoring for system stability indicators and kernel panic events that may indicate exploitation attempts. Additional defensive measures include restricting access to graphics subsystems where possible and maintaining comprehensive system logging to detect unusual display driver behavior. The vulnerability resolution aligns with standard kernel security practices for preventing null pointer dereferences and demonstrates the importance of thorough parameter validation in kernel space code, particularly in graphics drivers where memory corruption can have severe system-wide consequences.