CVE-2020-11608 in Linux
Summary
by MITRE
An issue was discovered in the Linux kernel before 5.6.1. drivers/media/usb/gspca/ov519.c allows NULL pointer dereferences in ov511_mode_init_regs and ov518_mode_init_regs when there are zero endpoints, aka CID-998912346c0d.
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Analysis
by VulDB Data Team • 10/18/2026
The vulnerability identified as CVE-2020-11608 represents a critical NULL pointer dereference flaw within the Linux kernel's USB video capture driver subsystem. This issue affects versions prior to 5.6.1 and specifically targets the gspca driver framework which handles various USB camera devices. The vulnerability manifests in the ov519.c driver module where two functions ov511_mode_init_regs and ov518_mode_init_regs fail to properly validate endpoint configurations before attempting to dereference pointers. When a USB camera device presents zero endpoints during initialization, these functions proceed to access memory locations that have not been allocated, resulting in kernel crashes and potential system instability. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which is a fundamental programming error that can lead to system crashes and denial of service conditions. The issue is particularly concerning as it occurs within kernel space where such failures can compromise entire system operations.
The technical exploitation of this vulnerability occurs during the initialization phase of USB video devices that utilize the gspca driver framework. When a device with zero endpoints is connected to a system running an affected kernel version, the driver attempts to process these endpoints without proper validation checks. The ov511_mode_init_regs and ov518_mode_init_regs functions contain logic that assumes endpoint structures will be properly initialized, but when zero endpoints are present, these assumptions break down. The functions proceed to dereference pointers that point to NULL or invalid memory locations, causing the kernel to crash with a segmentation fault. This behavior aligns with ATT&CK technique T1499.001 which involves network denial of service attacks, as the system becomes unresponsive due to kernel crashes. The vulnerability represents a classic example of insufficient input validation where the driver fails to handle edge cases properly, specifically the scenario of zero endpoint configurations.
The operational impact of CVE-2020-11608 extends beyond simple system crashes to potentially affect critical infrastructure and embedded systems that rely on USB video capture functionality. Systems utilizing USB cameras for surveillance, industrial inspection, or medical imaging applications could experience unexpected service interruptions when affected devices are connected. The vulnerability affects a wide range of hardware including various webcam models, digital cameras, and video capture devices that use the gspca driver framework. In enterprise environments, this could lead to widespread disruption of video conferencing systems, security monitoring, and automated inspection processes. The denial of service nature of this vulnerability means that attackers could potentially trigger system crashes repeatedly, leading to persistent availability issues. Organizations running kernel versions prior to 5.6.1 face significant risk as this vulnerability can be exploited through simple device connection events without requiring any special privileges or user interaction.
Mitigation strategies for CVE-2020-11608 primarily focus on immediate kernel updates to versions 5.6.1 or later where the vulnerability has been addressed through proper NULL pointer validation. System administrators should prioritize patching affected systems, particularly those running embedded systems or devices with limited update capabilities. The fix implemented in the patched kernel versions involves adding proper validation checks before attempting to access endpoint structures, ensuring that functions handle zero endpoint scenarios gracefully without attempting to dereference NULL pointers. Additional protective measures include implementing proper device access controls and monitoring for unusual USB device connection patterns that might indicate exploitation attempts. Organizations should also consider deploying kernel lockdown mechanisms and restricting USB device access to authorized users only. The vulnerability highlights the importance of proper input validation in kernel space code and demonstrates how seemingly minor edge case handling can lead to critical system instability. Security teams should monitor for related vulnerabilities in similar driver frameworks and ensure comprehensive testing of device initialization routines to prevent similar issues from emerging in other kernel subsystems.