CVE-2026-68215 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
media: radio-si476x: Unregister v4l2_device on probe failure
si476x_radio_probe() registers radio->v4l2dev before allocating the V4L2 controls and before registering the video device. If any of those later steps fails, probe returns through the exit label after freeing only the control handler.
A failed probe does not call si476x_radio_remove(), so the v4l2_device_unregister() there is not reached. This leaves the parent device reference taken by v4l2_device_register() behind on the error path.
Unregister the V4L2 device in the probe error path after freeing the controls.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability described represents a resource management issue within the Linux kernel's media subsystem, specifically affecting the si476x radio driver implementation. This flaw occurs during the device probe phase when the kernel attempts to initialize a radio device using the si476x driver. The problem manifests as an improper cleanup sequence that leaves residual references in the V4L2 device framework, creating potential memory leaks and device state inconsistencies.
The technical root cause stems from the probe function si476x_radio_probe() executing operations in an incorrect order. The function first registers the radio->v4l2dev device reference before proceeding to allocate V4L2 controls and register the video device itself. When subsequent initialization steps fail, the function returns through an exit path that only frees the control handler while leaving the v4l2_device_unregister() call unreachable. This violates proper resource cleanup protocols and creates a dangling reference in the kernel's device management framework.
This vulnerability impacts system stability and security by allowing potential memory leaks that could accumulate over time or be exploited for denial of service attacks. The improper cleanup leaves references to device structures that should have been properly released, potentially causing conflicts with future device initialization attempts or creating inconsistencies in device state tracking. From a cybersecurity perspective, such resource management flaws can serve as entry points for attackers seeking to exploit system instability or create persistent resource exhaustion conditions.
The operational impact of this vulnerability extends beyond simple memory leaks to affect the reliability of media device handling within Linux systems. When the probe fails due to hardware incompatibility, missing dependencies, or configuration errors, the improper cleanup can prevent subsequent re-probe attempts from succeeding correctly. This creates a cascading effect where failed device initialization attempts leave behind corrupted state information that affects the overall media subsystem performance and stability.
Security mitigations for this vulnerability involve implementing proper error handling within the probe function to ensure that all registered resources are properly cleaned up regardless of initialization success or failure. The fix requires modifying the exit path to unregister the v4l2_device before freeing the control handler, ensuring that device references are properly released even when probe operations fail. This approach aligns with best practices for resource management in kernel space and follows the principle of least privilege by preventing unintended resource exposure.
From an industry standards perspective, this vulnerability maps to CWE-459 which describes incomplete cleanup issues in software systems. The flaw demonstrates a classic example of improper resource management where cleanup operations are not performed consistently across all execution paths. The ATT&CK framework would categorize this under privilege escalation or denial of service techniques, as the resource leak could potentially be exploited to exhaust system resources or create unstable device states that affect system availability.
The fix implementation requires careful attention to ensure that the v4l2_device_unregister() call occurs in the correct sequence within the error handling path. This modification ensures that all device references created during probe initialization are properly released, preventing accumulation of stale references that could lead to system instability or security vulnerabilities. The solution maintains backward compatibility while addressing the core resource management issue through proper cleanup ordering.
This vulnerability highlights the critical importance of robust error handling in kernel drivers where improper resource cleanup can have significant implications for system stability and security. The fix demonstrates the necessity of following established patterns for device initialization and cleanup, particularly in complex subsystems like V4L2 where multiple device references and dependencies must be managed correctly to prevent resource leaks and maintain system integrity.