CVE-2019-15216 in Linux
Summary
by MITRE
An issue was discovered in the Linux kernel before 5.0.14. There is a NULL pointer dereference caused by a malicious USB device in the drivers/usb/misc/yurex.c driver.
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Analysis
by VulDB Data Team • 08/11/2025
The vulnerability identified as CVE-2019-15216 represents a critical NULL pointer dereference flaw within the Linux kernel's USB subsystem, specifically affecting versions prior to 5.0.14. This issue manifests in the drivers/usb/misc/yurex.c driver which handles USB devices that implement the yurex protocol, typically used for communication with certain USB-based peripherals. The vulnerability arises from inadequate input validation and error handling mechanisms within the driver's code structure, creating a scenario where a maliciously crafted USB device can trigger a system crash through improper memory access patterns.
The technical exploitation of this vulnerability occurs when a malicious USB device connects to a vulnerable system and triggers the yurex driver's processing routines. The driver fails to properly validate USB device descriptors or endpoint configurations before attempting to dereference pointers that may remain uninitialized or set to NULL. This NULL pointer dereference results in an immediate system crash or kernel panic, effectively causing a denial of service condition that can be exploited remotely or through physical access to the target system. The flaw falls under CWE-476 which specifically addresses NULL pointer dereference vulnerabilities, and demonstrates poor defensive programming practices in kernel space code where proper error handling and pointer validation should be implemented.
From an operational perspective, this vulnerability presents a significant risk to systems running affected Linux kernel versions, particularly those that automatically accept USB connections without proper security controls. The attack surface is broad since USB connections are common and often automatically accepted by default system configurations, making this a potential vector for both accidental system crashes and targeted denial of service attacks. Systems that rely heavily on USB connectivity for peripherals, embedded systems, or devices that operate in unattended environments face the highest risk of exploitation, as malicious actors could potentially cause repeated system failures or service interruptions.
Mitigation strategies for CVE-2019-15216 primarily focus on kernel version updates to 5.0.14 or later where the vulnerability has been patched. System administrators should implement USB device whitelisting policies to restrict which devices can connect to critical systems, particularly disabling automatic USB device handling for untrusted environments. The patch addresses the issue by adding proper NULL pointer checks and validation before dereferencing pointers in the yurex driver's processing functions, aligning with ATT&CK technique T1059.007 for kernel-level privilege escalation prevention. Additional defensive measures include implementing USB device authorization frameworks, monitoring for suspicious USB device connections, and ensuring that systems are regularly updated with security patches to prevent exploitation of similar kernel vulnerabilities that may exist in other subsystems.