CVE-2024-49892 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Initialize get_bytes_per_element's default to 1
Variables, used as denominators and maybe not assigned to other values, should not be 0. bytes_per_element_y & bytes_per_element_c are initialized by get_bytes_per_element() which should never return 0.
This fixes 10 DIVIDE_BY_ZERO issues reported by Coverity.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2024-49892 resides within the Linux kernel's display subsystem, specifically in the AMD display driver component under the direct rendering manager framework. This issue manifests as a divide-by-zero condition that could potentially compromise system stability and security. The flaw occurs in the drm/amd/display driver module where the get_bytes_per_element function is responsible for determining the byte size of display elements. The root cause stems from improper initialization of variables that serve as denominators in mathematical operations, creating a scenario where division by zero could occur during display processing operations.
The technical implementation of this vulnerability involves the initialization of two critical variables bytes_per_element_y and bytes_per_element_c within the display processing pipeline. These variables are intended to represent the number of bytes per element for luma and chroma components respectively, but they are not properly initialized before being used in division operations. When get_bytes_per_element() fails to return a valid non-zero value due to incomplete initialization or processing errors, these variables retain their default state which may include zero values. This creates a direct pathway for divide-by-zero exceptions when the system attempts to calculate display parameters or perform memory operations involving these uninitialized variables. The Coverity static analysis tool identified ten distinct instances of this pattern, highlighting the widespread nature of the uninitialized variable issue across the codebase.
The operational impact of CVE-2024-49892 extends beyond simple system instability, potentially enabling denial of service attacks or system crashes that could be exploited by malicious actors. When a divide-by-zero condition occurs in kernel space, it typically results in a kernel panic or system crash, effectively denying legitimate users access to system resources. This vulnerability affects systems utilizing AMD graphics hardware through the Linux kernel's display management framework, potentially impacting desktop environments, server configurations, and embedded systems that rely on AMD GPU acceleration. The vulnerability's classification aligns with CWE-369, which specifically addresses the divide-by-zero error condition that can lead to system instability and potential privilege escalation. Attackers could potentially exploit this weakness to cause system downtime or leverage it as part of a broader attack chain targeting system availability.
Mitigation strategies for CVE-2024-49892 should focus on implementing proper variable initialization and defensive programming practices within the kernel display subsystem. The primary fix involves ensuring that get_bytes_per_element() function always returns a valid non-zero value, with default initialization of bytes_per_element_y and bytes_per_element_c variables to 1 as specified in the patch. System administrators should prioritize applying the kernel updates that contain this fix, particularly in production environments where system stability is critical. Additionally, implementing proper input validation and error handling within display driver components can prevent similar issues from occurring in the future. Organizations should also consider monitoring for similar patterns in other kernel subsystems and implementing comprehensive static analysis tools to identify potential divide-by-zero conditions. The fix aligns with ATT&CK technique T1499.004, which involves system disruption through resource exhaustion or system instability, making proper kernel patching essential for maintaining system integrity and availability in enterprise environments.