CVE-2024-46816 in Linux
Summary
by MITRE • 09/27/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links
[Why]
Coverity report OVERRUN warning. There are only max_links elements within dc->links. link count could up to AMDGPU_DM_MAX_DISPLAY_INDEX 31.
[How]
Make sure link count less than max_links.
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Analysis
by VulDB Data Team • 11/19/2025
The vulnerability identified as CVE-2024-46816 resides within the Linux kernel's amdgpu display driver component, specifically within the drm/amd/display subsystem. This issue manifests as a potential buffer overrun condition that could compromise system stability and security. The flaw occurs during the initialization phase of the amdgpu_dm display manager when processing display link configurations. The vulnerability stems from insufficient bounds checking on display link counts, creating a scenario where the driver attempts to access memory beyond the allocated array boundaries for display links.
The technical implementation of this vulnerability involves a classic buffer overrun condition where the driver maintains a fixed-size array dc->links with a maximum capacity defined by max_links. However, the link counting mechanism does not properly validate that the actual number of display links does not exceed this predefined limit. When the system encounters display configurations with link counts approaching or exceeding AMDGPU_DM_MAX_DISPLAY_INDEX of 31, the driver fails to enforce proper boundary checks, leading to potential memory corruption. This type of vulnerability aligns with CWE-129, which addresses insufficient bounds checking, and CWE-787, which covers out-of-bounds write operations.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable privilege escalation and denial of service conditions. When the amdgpu_dm driver initializes with excessive display links, it can cause kernel memory corruption that may result in system crashes, data loss, or in severe cases, allow malicious actors to execute arbitrary code with kernel privileges. The vulnerability affects systems running Linux kernels with amdgpu display drivers, particularly those managing complex multi-display configurations or systems with extensive graphics hardware setups. Attackers could potentially exploit this condition by configuring display topologies that exceed the expected link limits, thereby triggering the buffer overrun during driver initialization.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and bounds checking within the amdgpu display driver initialization code. The fix requires ensuring that link counts are strictly validated against the maximum allowed links before any array access operations occur. System administrators should prioritize applying kernel updates that contain the patched amdgpu driver code, as these updates typically include the necessary bounds checking mechanisms. Additionally, monitoring systems for unusual display configuration changes or kernel panic events can help identify potential exploitation attempts. The fix addresses the underlying issue by implementing proper validation logic that prevents link counts from exceeding max_links, thereby eliminating the possibility of accessing memory outside the allocated array boundaries. This remediation aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel exploits, by preventing the conditions that could enable such attacks. Organizations should also consider implementing display configuration policies that prevent excessive link counts in multi-display setups to reduce the attack surface.