CVE-2026-72484 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
staging: most: video: avoid double free on video register failure
comp_register_videodev() allocates a video_device with video_device_alloc() and releases it if video_register_device() fails.
This can double free the video_device when __video_register_device() reaches device_register() and that call fails:
video_register_device() -> __video_register_device() -> device_register() fails -> put_device(&vdev->dev) -> v4l2_device_release() -> vdev->release(vdev) -> video_device_release(vdev)
comp_register_videodev() -> video_device_release(mdev->vdev)
Use video_device_release_empty() while registering the device so that registration failure paths do not free mdev->vdev through vdev->release(). comp_register_videodev() then releases mdev->vdev exactly once on failure. Restore video_device_release() after successful registration so the registered device keeps its normal lifetime handling.
This issue was found by a static analysis tool I am developing.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel's staging drivers, specifically within the most video subsystem, represents a critical double free condition that can lead to arbitrary code execution and system instability. This flaw occurs during the video device registration process where improper resource management creates a scenario where the same memory allocation is freed twice, potentially allowing attackers to exploit this behavior for privilege escalation or denial of service attacks. The issue stems from the complex interaction between multiple kernel subsystems including the video4linux2 framework, device registration mechanisms, and memory management routines.
The technical root cause involves the comp_register_videodev() function which allocates a video_device structure using video_device_alloc() and subsequently attempts to register it through video_register_device(). When the registration process fails during the device_register() call within __video_register_device(), the system triggers a cascade of cleanup operations that inadvertently causes a double free scenario. The failure path executes put_device() on the video device, which calls v4l2_device_release(), leading to vdev->release() invocation that ultimately calls video_device_release(). However, the comp_register_videodev() function itself also attempts to release mdev->vdev through the same video_device_release() path, creating the double free condition. This behavior directly violates the principle of single ownership in memory management and can be classified as a CWE-415: Double Free vulnerability.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling malicious actors to execute arbitrary code with kernel privileges. When exploited, the double free condition can corrupt kernel memory structures, leading to information disclosure, privilege escalation, or complete system compromise. The vulnerability affects systems running Linux kernels that include the staging drivers most video subsystem, particularly those utilizing video4linux2 framework components. Attackers could leverage this weakness to gain root access or cause persistent system instability through carefully crafted device registration sequences. The static analysis tool that discovered this issue highlights the importance of automated security verification in kernel code, aligning with ATT&CK technique T1068: Exploitation for Privilege Escalation and T1499.004: Endpoint Denial of Service.
The mitigation strategy implemented addresses the core issue by introducing video_device_release_empty() during the device registration phase to prevent premature freeing of resources. This approach ensures that mdev->vdev is released exactly once during failure conditions, while restoring normal video_device_release() behavior after successful registration. The fix follows established kernel security practices for managing device lifecycle events and prevents the memory corruption patterns associated with double free vulnerabilities. Additionally, this remediation aligns with industry best practices for secure kernel development and demonstrates the importance of proper resource management in kernel subsystems, particularly when dealing with complex registration and cleanup sequences that span multiple kernel components and subsystem interfaces.