CVE-2025-38316 in Linux
Summary
by MITRE • 07/10/2025
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7996: avoid NULL pointer dereference in mt7996_set_monitor()
The function mt7996_set_monitor() dereferences phy before the NULL sanity check.
Fix this to avoid NULL pointer dereference by moving the dereference after the check.
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Analysis
by VulDB Data Team • 12/07/2025
The vulnerability identified as CVE-2025-38316 represents a critical null pointer dereference flaw within the Linux kernel's wireless subsystem, specifically affecting the MediaTek mt7996 wireless driver implementation. This issue resides in the mt7996_set_monitor() function which handles monitor mode configuration for MediaTek wireless hardware. The flaw demonstrates a classic programming error where the function attempts to dereference a pointer to the phy structure before performing the necessary null validation check, creating a potential crash condition that could be exploited by malicious actors.
The technical implementation of this vulnerability stems from improper code ordering in the function's execution flow. During the wireless driver's monitor mode setup process, the mt7996_set_monitor() function accesses the phy parameter without first validating whether it contains a valid reference. This violates fundamental defensive programming principles and creates an execution path where a null pointer dereference can occur. The specific code pattern indicates that the phy structure pointer is accessed in a memory operation before the conditional null check, allowing execution to proceed to an invalid memory access when phy is NULL.
The operational impact of this vulnerability extends beyond simple system instability, as it can result in denial of service conditions that may persist until system reboot. When a null pointer dereference occurs in kernel space, the system typically experiences a kernel panic or system crash, which can disrupt wireless connectivity for extended periods. This is particularly concerning for embedded systems and network infrastructure devices that rely heavily on wireless connectivity, as such disruptions can affect network availability and potentially provide attackers with a means to cause persistent service degradation. The vulnerability affects systems running Linux kernels with MediaTek mt7996 wireless drivers, making it relevant to a broad range of devices including routers, access points, and embedded network equipment.
Mitigation strategies for this vulnerability should prioritize immediate kernel updates from Linux kernel maintainers, as the fix involves a simple but critical code reordering change. The recommended solution requires moving the phy pointer dereference operation to occur after the null validation check, which aligns with established secure coding practices and CWE-476 principles for null pointer dereference prevention. System administrators should implement patch management procedures to ensure all affected devices receive the corrected kernel version promptly. Additionally, monitoring network traffic for unusual patterns that might indicate exploitation attempts can provide early detection capabilities, though the vulnerability itself does not appear to enable arbitrary code execution or privilege escalation. Organizations should also consider implementing network segmentation and access controls to limit potential impact if exploitation were to occur in environments with critical network infrastructure.