CVE-2026-93225 in Linux
Summary
by MITRE • 09/24/2026
In the Linux kernel, the following vulnerability has been resolved:
phy: fsl-imx8mq-usb: fix typec switch leak on probe error path
If probe fails after imx95_usb_phy_get_tca() succeeds, the typec switch leaks because the only cleanup path was in .remove(), which never runs on probe failure.
Use devm_add_action_or_reset() so the switch is cleaned up on both probe failure and driver removal. The imx95_usb_phy_put_tca() is no longer needed, it will be removed in .remove() too.
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Analysis
by VulDB Data Team • 09/24/2026
The Linux kernel driver for the NXP i.MX8MQ USB PHY contains a resource management flaw that results in a type-C switch leak during the device probe phase. This vulnerability arises from an asymmetry in cleanup logic where resources allocated successfully during initialization are not properly released if subsequent steps within the same initialization sequence fail. Specifically, when the function imx95_usb_phy_get_tca succeeds but a later step in the probe routine encounters an error and returns a failure code, the driver fails to release the acquired type-C switch reference. The original implementation relied solely on the remove callback for cleanup, which is only invoked if the device has been successfully probed and added to the system bus. Consequently, any early exit from the probe function due to configuration errors or hardware unavailability leaves the kernel with a dangling reference to the type-C switch resource that is never freed until potentially much later or not at all depending on driver unload timing, leading to memory leaks and potential exhaustion of available switch handles over time.
This issue falls under CWE-401, which describes missing release of memory after successful allocation, as well as CWE-756, related to incorrect relative calculation of resource pointer offsets in some contexts where cleanup paths are misaligned with acquisition points. From a threat modeling perspective using the MITRE ATT&CK framework for enterprise systems, this type of defect can be categorized under T1496, Resource Hijacking, specifically as part of Denial of Service via resource exhaustion if an attacker or automated process triggers repeated probe failures on affected devices. While typically considered a low-severity bug in isolation due to its reliance on specific hardware initialization sequences failing repeatedly, it represents a fundamental flaw in driver lifecycle management that violates the principle of balanced resource acquisition and release.
The resolution involves refactoring the error handling path within the probe function by utilizing devm_add_action_or_reset(). This kernel API ensures that any action registered via this mechanism is automatically executed when the device's managed resources are released, which occurs both during normal driver removal and immediately upon a failed probe attempt. By binding the cleanup of the type-C switch to the device management lifecycle rather than relying on explicit calls in separate functions, the code guarantees consistent resource deallocation regardless of where the initialization process terminates. The function imx95_usb_phy_put_tca() is no longer required as an independent call because its functionality is now encapsulated within the managed action registered during successful acquisition, thereby simplifying the control flow and eliminating the possibility of human error in manual cleanup sequencing.
To mitigate similar vulnerabilities in other kernel drivers or embedded systems firmware, developers should prioritize the use of device-managed resource allocation APIs such as devm_kmalloc, devm_ioremap, and devm_add_action_or_reset for any resources that require explicit release upon driver detachment or probe failure. This approach enforces a deterministic cleanup model where resource lifetime is tied to the device object rather than manual function calls scattered across multiple control paths. Regular static analysis of error handling branches in initialization routines can also help identify cases where early returns bypass necessary teardown logic, ensuring robustness against partial initialization failures and maintaining system stability over long uptime periods.