CVE-2025-38144 in Linux
Summary
by MITRE • 07/03/2025
In the Linux kernel, the following vulnerability has been resolved:
watchdog: lenovo_se30_wdt: Fix possible devm_ioremap() NULL pointer dereference in lenovo_se30_wdt_probe()
devm_ioremap() returns NULL on error. Currently, lenovo_se30_wdt_probe() does not check for this case, which results in a NULL pointer dereference.
Add NULL check after devm_ioremap() to prevent this issue.
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Analysis
by VulDB Data Team • 04/18/2026
The vulnerability described in CVE-2025-38144 represents a critical null pointer dereference flaw within the Linux kernel's watchdog subsystem, specifically affecting the lenovo_se30_wdt driver. This issue occurs during the device probe phase when the kernel attempts to map memory resources for a Lenovo SE30 watchdog device. The vulnerability stems from inadequate error handling in the device initialization routine where the driver fails to validate the return value from the devm_ioremap() function before proceeding with subsequent operations. According to CWE-476, this represents a null pointer dereference vulnerability that can lead to system instability and potential denial of service conditions.
The technical implementation of this flaw involves the lenovo_se30_wdt_probe() function which is responsible for initializing the watchdog device driver during system boot or device enumeration. When devm_ioremap() encounters an error during memory mapping operations, it returns a NULL pointer to indicate failure, but the current driver implementation does not perform this crucial validation check. This oversight creates a scenario where the driver continues execution assuming successful memory mapping while actually operating on a NULL pointer reference, leading to immediate system crashes or kernel oops conditions. The vulnerability directly impacts the kernel's device management framework and represents a failure in proper error handling practices that are fundamental to robust kernel development.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise the reliability of embedded systems and server environments that rely on watchdog functionality for system monitoring and automatic recovery. In enterprise settings, this could result in unexpected system shutdowns or reboot cycles that disrupt service availability, particularly in mission-critical infrastructure where watchdog timers are essential for maintaining system integrity. The vulnerability affects systems running Linux kernels that include the lenovo_se30_wdt driver, making it relevant to a broad range of hardware platforms including Lenovo devices and potentially other systems that utilize similar watchdog implementations. From an attack perspective, this represents a denial of service vector that could be exploited to destabilize systems or potentially create conditions for more sophisticated attacks.
Mitigation strategies for this vulnerability focus primarily on implementing proper error handling procedures within the kernel driver code. The recommended fix involves adding a NULL pointer validation check immediately after the devm_ioremap() function call within the lenovo_se30_wdt_probe() function, ensuring that the driver gracefully handles memory mapping failures. This approach aligns with established kernel development practices and security guidelines that emphasize defensive programming techniques to prevent null pointer dereferences. System administrators should prioritize applying kernel updates that include this fix, particularly in production environments where watchdog functionality is critical. The remediation also reinforces principles from the ATT&CK framework's defensive security practices, specifically focusing on kernel-level integrity protection and proper resource management to prevent exploitation of low-level system vulnerabilities. Organizations should also consider implementing monitoring solutions to detect potential exploitation attempts and maintain comprehensive system logs for forensic analysis.