CVE-2024-53203 in Linux
Summary
by MITRE • 12/27/2024
In the Linux kernel, the following vulnerability has been resolved:
usb: typec: fix potential array underflow in ucsi_ccg_sync_control()
The "command" variable can be controlled by the user via debugfs. The worry is that if con_index is zero then "&uc->ucsi->connector[con_index
- 1]" would be an array underflow.
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Analysis
by VulDB Data Team • 12/15/2025
The vulnerability CVE-2024-53203 represents a critical array underflow condition within the Linux kernel's USB Type-C subsystem, specifically in the ucsi_ccg_sync_control() function. This flaw exists within the USB Type-C Connector Specification Interface (UCSI) implementation that manages communication between the host system and USB Type-C controllers. The issue stems from improper input validation where a user-controllable variable named "command" can be manipulated through the debugfs interface, creating a potential security risk that could be exploited by malicious actors with access to the system.
The technical flaw occurs when the con_index parameter equals zero, causing the expression "&uc->ucsi->connector[con_index - 1]" to reference an invalid memory location before the beginning of the connector array. This array underflow condition violates fundamental memory safety principles and can lead to unpredictable behavior including system crashes, memory corruption, or potentially privilege escalation. The vulnerability is classified as a CWE-129 weakness, specifically an "Improper Validation of Array Index" where the system fails to validate that the array index remains within acceptable bounds before accessing memory locations. The root cause demonstrates poor input validation practices where user-supplied data from debugfs is not properly sanitized or checked against array boundaries.
The operational impact of this vulnerability extends beyond simple system instability, as it represents a potential attack vector that could be exploited to compromise system integrity. An attacker with local access to the system could manipulate the debugfs interface to trigger the array underflow condition, potentially leading to denial of service attacks or more severe consequences depending on the system configuration and privileges available. The vulnerability is particularly concerning in embedded systems or devices where USB Type-C functionality is heavily utilized, as it could be leveraged to disrupt critical operations. This issue aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: PowerShell and T1547.001 for Registry Run Keys / Startup Folder, as it could enable persistent access through debugfs manipulation.
Mitigation strategies should focus on immediate kernel updates from the vendor to address the array validation issue, alongside implementing proper input validation controls that ensure con_index values remain within acceptable ranges before array access occurs. System administrators should restrict access to debugfs interfaces where possible and monitor for unusual activity patterns that might indicate exploitation attempts. Additional protective measures include implementing kernel hardening techniques such as stack canaries, address space layout randomization, and kernel module signing to prevent unauthorized modifications. The fix should implement proper boundary checking that validates con_index against the connector array size before any memory access occurs, ensuring that negative array indices cannot be computed. Organizations should also consider implementing network segmentation and access controls to limit potential attack surfaces where USB Type-C interfaces are present, particularly in enterprise environments where such vulnerabilities could be leveraged for lateral movement or privilege escalation attacks.