CVE-2025-38281 in Linux
Summary
by MITRE • 07/10/2025
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7996: Add NULL check in mt7996_thermal_init
devm_kasprintf() can return a NULL pointer on failure,but this returned value in mt7996_thermal_init() is not checked. Add NULL check in mt7996_thermal_init(), to handle kernel NULL pointer dereference error.
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Analysis
by VulDB Data Team • 12/07/2025
The vulnerability identified as CVE-2025-38281 resides within the Linux kernel's wireless subsystem, specifically affecting the mt7996 wireless driver implementation. This issue manifests in the mt76 wireless driver framework which supports various MediaTek wireless chipsets including the mt7996 model. The flaw occurs during the thermal initialization phase of the wireless device management process, where proper error handling mechanisms are missing. The vulnerability represents a classic null pointer dereference scenario that can lead to system instability and potential security implications within kernel space operations.
The technical root cause stems from the function mt7996_thermal_init() which invokes devm_kasprintf() to allocate and format strings for thermal management purposes. The devm_kasprintf() function is a kernel memory allocation utility that may return NULL on memory allocation failures, a condition that the current implementation fails to properly handle. When this NULL value is returned and subsequently used without validation, it creates a scenario where the kernel attempts to dereference a null pointer, leading to immediate system termination or crash. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, representing a fundamental error handling weakness in kernel space programming. The vulnerability directly aligns with ATT&CK technique T1068 which describes the exploitation of system vulnerabilities through kernel-level attacks.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation or denial of service conditions within wireless networking operations. When the wireless driver fails to initialize properly due to the null pointer dereference, it can result in complete wireless functionality loss for affected devices. Systems utilizing MediaTek mt7996 wireless chipsets, particularly those in enterprise or embedded environments where wireless connectivity is critical, face significant operational risks. The vulnerability can be triggered through normal wireless device initialization processes, making it particularly concerning as it does not require special privileges or specific user interactions to manifest. This characteristic places it within the ATT&CK framework's T1499 category of network denial of service attacks, as it can effectively disable wireless networking capabilities.
Mitigation strategies for CVE-2025-38281 primarily involve applying the kernel patch that introduces proper NULL pointer checking in the mt7996_thermal_init() function. The fix implements a straightforward defensive programming approach by validating the return value of devm_kasprintf() before proceeding with subsequent operations. This patch demonstrates the importance of robust error handling in kernel space code, where memory allocation failures must be explicitly checked and handled to prevent system crashes. Organizations should prioritize updating their kernel versions to include this fix, particularly in environments where wireless connectivity reliability is paramount. Additionally, system administrators should monitor for any unusual wireless connectivity issues that might indicate the presence of this vulnerability, as the crash behavior may manifest as intermittent wireless failures rather than complete system shutdowns. The vulnerability highlights the critical need for comprehensive testing of kernel memory allocation functions and proper error propagation mechanisms in wireless driver implementations.