CVE-2024-50288 in Linux
Summary
by MITRE • 11/19/2024
In the Linux kernel, the following vulnerability has been resolved:
media: vivid: fix buffer overwrite when using > 32 buffers
The maximum number of buffers that can be requested was increased to 64 for the video capture queue. But video capture used a must_blank array that was still sized for 32 (VIDEO_MAX_FRAME). This caused an out-of-bounds write when using buffer indices >= 32.
Create a new define MAX_VID_CAP_BUFFERS that is used to access the must_blank array and set max_num_buffers for the video capture queue.
This solves a crash reported by:
https://bugzilla.kernel.org/show_bug.cgi?id=219258
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Analysis
by VulDB Data Team • 07/16/2025
The vulnerability CVE-2024-50288 represents a critical buffer management flaw within the Linux kernel's vivid media driver, which is part of the video capture subsystem. This issue specifically affects the video capture queue implementation where the kernel developers had increased the maximum number of buffers that can be requested from 32 to 64, aligning with the VIDEO_MAX_FRAME constant that traditionally capped buffer allocation at 32. However, this enhancement was not consistently applied across all internal data structures, creating a significant memory safety gap. The vivid driver, which is used for testing and development purposes in video capture scenarios, failed to update its internal must_blank array sizing, leaving it fixed at 32 elements despite the expanded buffer capacity.
The technical flaw manifests as an out-of-bounds write condition that occurs when buffer indices exceed 32, specifically when userspace applications attempt to utilize the expanded buffer pool beyond the original 32-buffer limit. This buffer overwrite vulnerability stems from a fundamental mismatch between the increased buffer allocation capacity and the statically sized must_blank array that tracks buffer states. When buffer indices reach 32 or higher, the code attempts to write beyond the allocated array boundaries, potentially corrupting adjacent memory regions and leading to unpredictable behavior. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and more specifically aligns with CWE-787, representing out-of-bounds write vulnerabilities that can result in arbitrary code execution or system crashes.
The operational impact of this vulnerability extends beyond simple system instability, as it represents a potential attack vector for privilege escalation and system compromise. When exploited, the buffer overwrite can lead to kernel crashes, data corruption, or more severe consequences if an attacker can control the memory corruption pattern to achieve code execution. The vulnerability affects systems running Linux kernels with the vivid media driver enabled, particularly those utilizing video capture functionality with buffer counts exceeding 32. This issue is particularly concerning in embedded systems, server environments, or any deployment where the kernel's media subsystem is actively used, as it can result in denial of service or potential privilege escalation attacks.
The mitigation strategy implemented by the kernel developers addresses this vulnerability through a targeted code fix that introduces a new define MAX_VID_CAP_BUFFERS to ensure consistent sizing across all relevant data structures. This approach aligns with the principle of defensive programming and memory safety best practices, where all array accesses are properly bounded by the actual allocated memory size. The fix ensures that the must_blank array is sized appropriately to match the maximum number of buffers that can be allocated, preventing any out-of-bounds memory access. This solution demonstrates proper adherence to the ATT&CK framework's defense evasion techniques by addressing memory corruption vulnerabilities at their root cause rather than implementing reactive patches. The resolution maintains backward compatibility while expanding the buffer capacity to 64 as intended, ensuring that legitimate use cases can leverage the expanded buffer pool without introducing memory safety issues. This vulnerability fix exemplifies the importance of thorough testing and code review processes, particularly when modifying system-level parameters that affect memory management and buffer allocation in kernel space.