CVE-2026-68220 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
media: nxp: imx8-isi: Add missing v4l2_subdev_cleanup() in crossbar and pipe
Both mxc_isi_crossbar_init() and mxc_isi_pipe_init() call v4l2_subdev_init_finalize() which allocates the subdev active state, but neither mxc_isi_crossbar_cleanup() nor mxc_isi_pipe_cleanup() calls v4l2_subdev_cleanup() to free it.
This causes a memory leak on every rmmod, reported by kmemleak:
unreferenced object 0xffff0000d06fc800 (size 192): comm "(udev-worker)", pid 254, jiffies 4294913455 backtrace (crc 36eeae58): kmemleak_alloc+0x34/0x40 __kvmalloc_node_noprof+0x5f8/0x7d8 __v4l2_subdev_state_alloc+0x1fc/0x30c __v4l2_subdev_init_finalize+0x178/0x368
Add the missing v4l2_subdev_cleanup() calls before media_entity_cleanup() in both crossbar and pipe cleanup paths.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability exists within the Linux kernel's media subsystem, specifically affecting the nxp imx8-isi driver that manages image sensor interfaces for i.MX 8 SoC platforms. The issue manifests as a memory leak during driver module removal operations, where the kernel's memory leak detection system kmemleak identifies unreferenced objects that should have been freed. The flaw occurs in the V4L2 subdevice management code where proper cleanup routines are not invoked during driver shutdown sequences.
The technical root cause stems from an incomplete implementation of the V4L2 subdevice lifecycle management pattern. Both mxc_isi_crossbar_init() and mxc_isi_pipe_init() functions correctly invoke v4l2_subdev_init_finalize() which allocates and initializes the subdevice active state structure through the __v4l2_subdev_state_alloc function. However, the corresponding cleanup functions mxc_isi_crossbar_cleanup() and mxc_isi_pipe_cleanup() fail to call v4l2_subdev_cleanup() before executing media_entity_cleanup(). This omission leaves the allocated subdevice state structures in memory, creating a persistent memory leak that accumulates each time the module is loaded and unloaded.
The operational impact of this vulnerability extends beyond simple memory consumption issues. While individual memory leaks may appear minor, repeated loading and unloading of the driver module can lead to significant memory fragmentation and gradual system resource depletion over time. The kmemleak report specifically shows a 192-byte object allocation that remains unreferenced, indicating that subsystem-level cleanup functions are not properly invoked during module teardown processes. This pattern violates established kernel development practices for resource management and can potentially affect system stability under prolonged usage scenarios.
The fix implemented addresses this by adding the missing v4l2_subdev_cleanup() calls in both cleanup paths before media_entity_cleanup() executes. This ensures proper deallocation of subdevice state structures that were allocated during initialization, following the standard V4L2 subsystem pattern for resource management. The solution aligns with CWE-404, which addresses improper resource release or unmanaged resource consumption, and follows ATT&CK technique T1547.006 for privilege escalation through kernel module manipulation. Additionally, this vulnerability demonstrates poor adherence to the Linux kernel's driver model best practices where all resources allocated during initialization must have corresponding cleanup operations during driver destruction to prevent memory leaks and maintain system integrity.