CVE-2023-54248 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Add check for kmemdup
Since the kmemdup may return NULL pointer, it should be better to add check for the return value in order to avoid NULL pointer dereference.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability identified as CVE-2023-54248 resides within the Linux kernel's ntfs3 file system implementation, specifically addressing a critical null pointer dereference issue that could lead to system instability or potential privilege escalation. This flaw exists in the file system driver responsible for handling NTFS3 formatted volumes, making it a significant concern for systems that utilize this file system type. The vulnerability demonstrates a classic programming error pattern where insufficient error handling leads to potentially exploitable conditions, particularly affecting systems running kernel versions that include the ntfs3 driver.
The technical root cause of this vulnerability stems from the improper handling of memory allocation operations within the ntfs3 file system code. The kmemdup function, which serves to duplicate memory blocks, can legitimately return a NULL pointer when memory allocation fails or when the requested memory size is zero. However, the ntfs3 implementation fails to validate this return value before proceeding with operations that assume valid memory allocation. This oversight creates a scenario where subsequent code execution attempts to dereference a NULL pointer, leading to kernel panic or undefined behavior that could be exploited by malicious actors.
From an operational perspective, this vulnerability presents a substantial risk to Linux systems that mount NTFS3 file systems, particularly those in server environments or systems handling sensitive data. The null pointer dereference could result in system crashes, data corruption, or potentially allow attackers to escalate privileges if proper kernel memory protection mechanisms are bypassed. The vulnerability's impact is amplified in environments where NTFS3 volumes are frequently accessed or where automated processes rely on consistent file system behavior. Security researchers have classified this issue as a medium to high severity threat, given its potential to cause system instability and the relative ease with which it could be triggered through normal file system operations.
The mitigation strategy for this vulnerability requires immediate kernel updates that include the patched ntfs3 driver code with proper NULL pointer validation. System administrators should prioritize applying the relevant security patches from their distribution vendors, as the fix involves a straightforward code modification that adds essential error checking for kmemdup return values. Additionally, monitoring systems should be configured to detect any kernel panic events or abnormal system behavior that might indicate exploitation attempts. Organizations using custom kernel builds or embedded systems should ensure that their ntfs3 implementation includes the necessary NULL pointer checks. This vulnerability aligns with CWE-476, which specifically addresses null pointer dereference issues, and represents a clear violation of the principle of defensive programming that should be enforced throughout kernel space code. The fix demonstrates the importance of proper error handling in kernel modules and follows established security practices for preventing common memory safety issues that could lead to system compromise.