CVE-2024-50244 in Linux
Summary
by MITRE • 11/09/2024
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Additional check in ni_clear()
Checking of NTFS_FLAGS_LOG_REPLAYING added to prevent access to uninitialized bitmap during replay process.
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Analysis
by VulDB Data Team • 10/02/2025
The vulnerability identified as CVE-2024-50244 resides within the Linux kernel's ntfs3 filesystem driver, specifically in the ni_clear() function that manages the clearing of NTFS file system structures. This issue represents a critical flaw in the kernel's handling of NTFS filesystem operations during the replay process, where the system attempts to recover from potential inconsistencies or crashes. The ntfs3 driver is responsible for managing NTFS version 3 filesystems which are commonly used in Windows environments and require proper kernel support for cross-platform compatibility. The vulnerability manifests when the system attempts to clear file system structures during recovery operations, creating a window where uninitialized memory structures could be accessed, potentially leading to system instability or security implications.
The technical root cause of this vulnerability stems from the absence of proper validation checks within the ni_clear() function. During the NTFS replay process, which occurs when the filesystem needs to recover from an inconsistent state or system crash, the kernel must ensure that all bitmap structures are properly initialized before any access occurs. The missing NTFS_FLAGS_LOG_REPLAYING check creates a scenario where the system attempts to access memory locations that have not yet been properly initialized, leading to potential memory corruption or undefined behavior. This flaw operates at the kernel level where the filesystem driver interacts directly with system memory and file system structures, making it particularly dangerous as it can affect the stability of the entire operating system.
The operational impact of this vulnerability extends beyond simple system crashes or performance degradation. When the NTFS replay process is triggered, typically following an unexpected shutdown or system failure, the uninitialized bitmap access can cause the kernel to behave unpredictably. This may result in system hangs, kernel oops messages, or even potential privilege escalation opportunities if attackers can manipulate the conditions that trigger this code path. The vulnerability affects systems running Linux kernels with ntfs3 filesystem support, particularly those that frequently encounter filesystem recovery scenarios or operate in environments where NTFS filesystems are commonly used. From an attack perspective, this vulnerability aligns with the ATT&CK technique of privilege escalation through kernel exploits and could potentially be leveraged by malicious actors to gain elevated system privileges.
The fix implemented for CVE-2024-50244 involves adding a straightforward but critical validation check that verifies the NTFS_FLAGS_LOG_REPLAYING flag before allowing access to the bitmap structures during the ni_clear() operation. This additional check ensures that the replay process properly initializes all necessary structures before any access occurs, preventing the race condition that led to the vulnerability. The solution follows established security practices for kernel development and aligns with CWE-457 which addresses the use of uninitialized variables in kernel code. Organizations should prioritize applying this patch as it addresses a fundamental flaw in the filesystem recovery mechanism that could be exploited in various scenarios including system recovery operations, automated backup processes, or environments where filesystem consistency is critical. The mitigation strategy involves updating to the patched kernel version and ensuring that all systems running ntfs3 filesystem support are properly updated to prevent exploitation of this vulnerability.