CVE-2025-38007 in Linux
Summary
by MITRE • 06/18/2025
In the Linux kernel, the following vulnerability has been resolved:
HID: uclogic: Add NULL check in uclogic_input_configured()
devm_kasprintf() returns NULL when memory allocation fails. Currently, uclogic_input_configured() does not check for this case, which results in a NULL pointer dereference.
Add NULL check after devm_kasprintf() to prevent this issue.
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Analysis
by VulDB Data Team • 02/02/2026
The vulnerability described in CVE-2025-38007 represents a critical null pointer dereference flaw within the Linux kernel's HID (Human Interface Device) subsystem, specifically affecting the uclogic driver used for tablet and digitizer devices. This issue resides in the uclogic_input_configured() function where the driver fails to properly validate memory allocation outcomes. The uclogic driver is responsible for handling input devices such as graphics tablets and drawing tablets that utilize the uclogic protocol, making this vulnerability particularly concerning for users relying on digitizer hardware for creative work, professional applications, or industrial touch screen interfaces. The flaw manifests when the devm_kasprintf() function, which dynamically allocates and formats strings for device identification, returns a NULL pointer upon memory allocation failure, but the subsequent code does not perform proper validation before attempting to use this potentially null reference.
The technical implementation of this vulnerability stems from improper error handling within the device configuration process of the uclogic driver. When devm_kasprintf() encounters memory allocation failure during string formatting operations required for device identification and configuration, it returns NULL instead of a valid memory pointer. The uclogic_input_configured() function then proceeds to use this NULL pointer without proper validation, leading to an immediate system crash or kernel panic. This type of null pointer dereference constitutes a classic software error pattern that can be classified under CWE-476 as "NULL Pointer Dereference" and falls under the broader category of memory safety issues. The vulnerability directly impacts the kernel's ability to properly initialize and configure input devices, potentially causing complete system instability when affected hardware is connected or when the driver attempts to process input events from such devices.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise the stability and reliability of Linux systems running affected kernel versions. Users experiencing this issue may encounter unexpected kernel panics or system lockups when connecting uclogic-compatible tablet devices, particularly in environments where such hardware is frequently used. This affects a wide range of devices including graphics tablets, drawing tablets, and various touch screen interfaces that utilize the uclogic protocol, making the vulnerability relevant for both consumer and enterprise users. The vulnerability is particularly concerning in production environments where system uptime is critical, as it can cause unexpected service interruptions and potentially lead to data loss if the system crashes during active input processing. From an attack perspective, while this vulnerability may not be directly exploitable for remote code execution, it can be leveraged to cause denial of service conditions that could be particularly disruptive in embedded systems or industrial control environments where stable operation is paramount.
The mitigation for CVE-2025-38007 involves implementing a simple but crucial null pointer validation check in the uclogic_input_configured() function following the devm_kasprintf() call. This fix aligns with standard secure coding practices and kernel development guidelines that emphasize proper error handling for all memory allocation operations. The solution follows the established pattern of checking return values from memory allocation functions before using the resulting pointers, which is fundamental to preventing null pointer dereference vulnerabilities. The fix should be applied through a kernel patch that adds a conditional check to verify whether devm_kasprintf() returned NULL, and if so, handle the error gracefully rather than proceeding with the null pointer dereference. This approach ensures that the kernel can properly report allocation failures and continue operating without crashing, maintaining system stability while still providing appropriate error logging for debugging purposes. The vulnerability resolution demonstrates the importance of following security best practices in kernel development, particularly regarding error handling and memory management, and reinforces the need for comprehensive testing of device drivers under memory stress conditions to prevent such issues from reaching production systems.