CVE-2023-53405 in Linux
Summary
by MITRE • 09/18/2025
In the Linux kernel, the following vulnerability has been resolved:
USB: gadget: gr_udc: fix memory leak with using debugfs_lookup()
When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To make things simpler, just call debugfs_lookup_and_remove() instead which handles all of the logic at once.
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Analysis
by VulDB Data Team • 12/13/2025
The vulnerability CVE-2023-53405 represents a memory leak condition within the Linux kernel's USB gadget framework, specifically affecting the gr_udc driver implementation. This issue manifests in the handling of debugfs filesystem operations where the kernel fails to properly release reference counts on debugfs entries, leading to gradual memory consumption over time. The vulnerability exists in the USB gadget subsystem which is responsible for managing USB device functions in kernel space, particularly when the system operates in gadget mode where the device presents itself to a host as a USB peripheral.
The technical flaw stems from improper resource management in the debugfs_lookup() function call sequence within the gr_udc driver code. When debugfs_lookup() is invoked to locate a debugfs entry, the returned reference must be explicitly released using dput() to decrement the reference count and allow proper memory deallocation. However, the implementation fails to execute this cleanup operation, causing the debugfs entry to remain in memory indefinitely. This memory leak occurs each time the debugfs_lookup() function is called without proper corresponding dput() invocation, creating a cumulative effect that degrades system performance over extended periods of operation. The vulnerability is classified as a memory leak under CWE-401 and represents a classic resource management error in kernel space programming.
The operational impact of this vulnerability extends beyond simple memory consumption as it can lead to system instability, reduced performance, and potential denial of service conditions in embedded systems or devices running Linux kernel versions containing this flaw. The memory leak accumulates over time, particularly in systems that frequently access USB gadget functionality or maintain long-running USB device operations. In production environments where USB gadget functionality is heavily utilized, such as industrial controllers, network appliances, or embedded systems, this vulnerability can cause gradual degradation of system resources until the device becomes unresponsive or requires manual rebooting to clear the accumulated memory leak. The issue affects systems using the gr_udc driver which is commonly found in various USB gadget implementations across different hardware platforms.
The fix for CVE-2023-53405 involves replacing the problematic debugfs_lookup() call with debugfs_lookup_and_remove() which consolidates the lookup and cleanup operations into a single atomic function call. This approach eliminates the possibility of memory leaks by ensuring that all necessary cleanup operations are performed automatically when the function is invoked. The solution aligns with the principle of defensive programming and follows best practices for kernel memory management as outlined in the Linux kernel documentation and security guidelines. This remediation approach is consistent with the ATT&CK framework's concept of privilege escalation through resource exhaustion, where improper resource management can lead to system instability and potential exploitation opportunities. The fix also demonstrates proper adherence to kernel coding standards that require explicit resource cleanup operations to prevent memory leaks in kernel space implementations.