CVE-2022-27223 in Linux
Summary
by MITRE • 03/16/2022
In drivers/usb/gadget/udc/udc-xilinx.c in the Linux kernel before 5.16.12, the endpoint index is not validated and might be manipulated by the host for out-of-array access.
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Analysis
by VulDB Data Team • 05/18/2025
The vulnerability identified as CVE-2022-27223 resides within the Linux kernel's USB gadget driver implementation, specifically in the xilinx udc driver located at drivers/usb/gadget/udc/udc-xilinx.c. This flaw represents a classic buffer overflow vulnerability that occurs when the kernel fails to properly validate endpoint indices received from host devices. The issue affects Linux kernel versions prior to 5.16.12, making it a significant concern for systems running older kernel versions that remain in production environments.
The technical root cause of this vulnerability stems from inadequate input validation within the USB gadget driver's endpoint handling mechanism. When a host device communicates with the USB gadget controller, it provides endpoint index values that the driver uses to access internal data structures. Without proper validation, an attacker-controlled endpoint index can cause the driver to access memory locations outside the intended array boundaries. This out-of-bounds memory access can lead to various security implications including data corruption, privilege escalation, or system instability.
From an operational perspective, this vulnerability creates a serious risk for embedded systems and devices that rely on USB gadget functionality, particularly those using xilinx USB controller hardware. The attack surface is significant because USB gadget drivers are commonly used in device-to-device communication scenarios, network appliances, and embedded systems where the device acts as a USB peripheral. An attacker with physical access to the device or the ability to control USB traffic could manipulate the endpoint index values to trigger the out-of-bounds access, potentially leading to system compromise or denial of service conditions.
This vulnerability maps directly to CWE-129, which describes improper validation of array index, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter usage in exploitation scenarios. The flaw represents a privilege escalation vector that could allow an attacker to gain elevated privileges within the kernel space, as the out-of-bounds access may enable memory corruption that can be leveraged for arbitrary code execution. The impact is particularly severe in embedded systems where kernel-level access can provide complete control over the device's functionality.
The recommended mitigation strategy involves upgrading the Linux kernel to version 5.16.12 or later, which includes the necessary patches to validate endpoint indices before use. Organizations should also implement monitoring for unusual USB gadget activity and consider disabling USB gadget functionality when not actively required. Additionally, system administrators should conduct thorough vulnerability assessments to identify all systems running affected kernel versions and prioritize patching based on risk assessment. The fix implemented in the patched kernel version ensures proper validation of endpoint indices through bounds checking mechanisms that prevent access to memory locations outside the allocated array boundaries, thereby eliminating the potential for out-of-bounds memory access.