CVE-2024-46814 in Linux
Summary
by MITRE • 09/27/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Check msg_id before processing transcation
[WHY & HOW]
HDCP_MESSAGE_ID_INVALID (-1) is not a valid msg_id nor is it a valid array index, and it needs checking before used.
This fixes 4 OVERRUN issues reported by Coverity.
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Analysis
by VulDB Data Team • 11/19/2025
The vulnerability identified as CVE-2024-46814 resides within the Linux kernel's AMD display subsystem, specifically within the digital rights management component responsible for handling HDCP (High-bandwidth Digital Content Protection) transactions. This flaw represents a classic buffer overread condition that occurs when processing display content protection messages. The vulnerability manifests in the drm/amd/display driver where the system fails to validate the message identifier before proceeding with transaction processing, creating a potential pathway for memory corruption and system instability.
The technical root cause of this vulnerability stems from improper input validation within the HDCP message handling logic. When the system receives a message with identifier HDCP_MESSAGE_ID_INVALID set to -1, it attempts to use this invalid value as an array index without proper bounds checking. This condition violates fundamental security principles and creates multiple buffer overread scenarios that can be exploited by malicious actors. The Coverity static analysis tool identified four distinct overread issues stemming from this single validation flaw, highlighting the severity and widespread nature of the problem within the codebase. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of inputs, and represents a clear violation of the principle of least privilege in memory access operations.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling attackers to execute arbitrary code within the kernel space or cause system crashes that could be exploited for denial-of-service attacks. The AMD display driver's HDCP functionality is critical for protecting high-definition content transmission, making this vulnerability particularly concerning for systems handling sensitive multimedia content. Attackers could leverage this flaw to manipulate display output, potentially accessing protected content or disrupting normal system operations. The vulnerability's classification aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation," as kernel-level memory corruption can provide attackers with elevated privileges and system control. Systems utilizing AMD graphics hardware with HDCP capabilities are particularly at risk, especially those in enterprise environments where display security is paramount.
Mitigation strategies for this vulnerability should prioritize immediate patch deployment from kernel maintainers, as the fix involves implementing proper validation checks before array indexing operations. Organizations should also consider implementing runtime monitoring to detect anomalous HDCP message processing patterns and establish network segmentation to limit exposure. The fix requires adding validation logic to ensure that msg_id values are within acceptable ranges before being used as array indices, effectively preventing the use of invalid identifiers like HDCP_MESSAGE_ID_INVALID. System administrators should monitor for any unusual display behavior or kernel panic messages that might indicate exploitation attempts, while also ensuring that all AMD graphics drivers and kernel versions are kept current with security patches. This vulnerability serves as a reminder of the critical importance of input validation in kernel space code and the potential consequences of inadequate bounds checking in security-sensitive components.