CVE-2024-39465 in Linux
Summary
by MITRE • 06/25/2024
In the Linux kernel, the following vulnerability has been resolved:
media: mgb4: Fix double debugfs remove
Fixes an error where debugfs_remove_recursive() is called first on a parent directory and then again on a child which causes a kernel panic.
[hverkuil: added Fixes/Cc tags]
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 04/07/2026
The vulnerability CVE-2024-39465 represents a critical kernel panic issue within the Linux media subsystem, specifically affecting the mgb4 driver implementation. This flaw manifests in the improper handling of debugfs directory removal operations, creating a scenario where the kernel's debug file system management becomes corrupted. The issue occurs during the cleanup phase of media device drivers, particularly those implementing the mgb4 hardware interface, where the kernel's debugfs subsystem experiences a state inconsistency that leads to system-wide crashes. The vulnerability directly impacts the stability and reliability of Linux systems running media-intensive workloads, particularly those utilizing hardware devices that depend on the mgb4 driver framework.
The technical root cause of this vulnerability stems from a flawed sequence in debugfs directory cleanup operations within the mgb4 media driver. When the driver attempts to remove debugfs entries during device teardown, it executes debugfs_remove_recursive() function calls in an incorrect order. The system first removes the parent debugfs directory and subsequently attempts to remove a child directory that no longer exists in the filesystem hierarchy. This double removal operation creates a kernel panic condition because the debugfs subsystem maintains internal data structures that become inconsistent when attempting to remove already-deleted entries. The flaw demonstrates a classic case of improper resource management and violates fundamental kernel safety principles for filesystem operations. This type of error falls under CWE-459, which specifically addresses incomplete cleanup issues in system resources, and represents a failure in proper resource lifecycle management within kernel space.
The operational impact of CVE-2024-39465 extends beyond simple system crashes to potentially compromise the entire media processing pipeline on affected Linux systems. When triggered, the kernel panic causes immediate system instability, forcing device drivers to become unresponsive and potentially leading to data loss or system reboot. This vulnerability affects any Linux kernel version containing the mgb4 driver implementation, particularly impacting embedded systems, media servers, and devices running real-time multimedia applications. The issue can be exploited through normal device operation or during driver initialization and cleanup phases, making it difficult to predict and prevent. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1068 which involves exploiting local system vulnerabilities, and T1490 which targets system destruction through kernel-level attacks. The vulnerability's exploitation requires minimal privileges and can be triggered by standard media device operations, making it particularly dangerous for production environments.
Mitigation strategies for CVE-2024-39465 focus on immediate kernel updates and code-level fixes to ensure proper debugfs directory cleanup sequences. The recommended approach involves applying the upstream patch that corrects the order of debugfs_remove_recursive() calls, ensuring that child directories are removed before their parent counterparts. System administrators should prioritize updating to kernel versions that include the fix, particularly those containing the mgb4 driver modifications. Additionally, implementing proper error handling in driver cleanup routines can provide additional protection against similar issues. Monitoring systems should be configured to detect kernel panic events and alert administrators to potential exploitation attempts. The fix addresses the core issue by ensuring proper resource management and prevents the kernel from attempting to remove non-existent debugfs entries. Organizations running critical media processing workloads should conduct thorough testing of updated kernel versions to ensure compatibility and stability before deployment. The vulnerability's resolution demonstrates the importance of proper kernel subsystem design and the necessity of rigorous testing for cleanup operations in device driver frameworks.