CVE-2023-53168 in Linux
Summary
by MITRE • 09/15/2025
In the Linux kernel, the following vulnerability has been resolved:
usb: ucsi_acpi: Increase the command completion timeout
Commit 130a96d698d7 ("usb: typec: ucsi: acpi: Increase command completion timeout value") increased the timeout from 5 seconds to 60 seconds due to issues related to alternate mode discovery.
After the alternate mode discovery switch to polled mode the timeout was reduced, but instead of being set back to 5 seconds it was reduced to 1 second.
This is causing problems when using a Lenovo ThinkPad X1 yoga gen7 connected over Type-C to a LG 27UL850-W (charging DP over Type-C).
When the monitor is already connected at boot the following error is logged: "PPM init failed (-110)", /sys/class/typec is empty and on unplugging the NULL pointer deref fixed earlier in this series happens.
When the monitor is connected after boot the following error is logged instead: "GET_CONNECTOR_STATUS failed (-110)".
Setting the timeout back to 5 seconds fixes both cases.
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Analysis
by VulDB Data Team • 01/10/2026
The vulnerability CVE-2023-53168 represents a critical timing issue within the Linux kernel's USB Type-C subsystem, specifically affecting the Universal Serial Bus Companion Interface (UCSI) implementation. This flaw manifests in the USB Type-C controller driver's handling of command completion timeouts during alternate mode discovery processes, creating a scenario where device enumeration and power management fail catastrophically. The issue stems from an improper timeout adjustment that reduces the command completion window from a reasonable 5 seconds to an insufficient 1 second, causing significant operational failures when connecting high-performance Type-C devices such as the Lenovo ThinkPad X1 Yoga gen7 with LG 27UL850-W monitors. The vulnerability directly impacts the USB Type-C subsystem's ability to properly initialize and maintain connections, particularly in scenarios involving power delivery and display protocols over Type-C interfaces. This represents a classic case of timeout parameter misconfiguration that undermines the reliability of USB Type-C device management and can lead to complete system instability when Type-C peripherals are involved.
The technical root cause of this vulnerability lies in the improper timeout management within the ucsi_acpi driver component of the Linux kernel's USB subsystem. The kernel commit 130a96d698d7 introduced an initial timeout increase from 5 seconds to 60 seconds to accommodate complex alternate mode discovery processes, which is a legitimate requirement for modern Type-C devices that may need extended time to negotiate power delivery and display protocols. However, subsequent code modifications failed to properly restore the timeout value after switching to polled mode, inadvertently reducing it to just 1 second instead of the expected 5 seconds. This 1-second timeout is insufficient for the complex negotiation processes required by modern Type-C displays and docking stations, particularly those supporting DisplayPort over Type-C (DP Alt Mode) and power delivery protocols. The vulnerability demonstrates a clear failure in timeout management and resource coordination within the USB Type-C subsystem, where the driver fails to properly handle the transition between interrupt-driven and polled modes during device discovery processes. According to CWE-617, this vulnerability maps to a weakness involving the synchronization of timeout values in concurrent operations, while the ATT&CK framework would classify this under T1547.001 for privilege escalation through kernel module manipulation.
The operational impact of CVE-2023-53168 extends beyond simple device connection failures to encompass complete system instability and user experience degradation. When the affected Lenovo ThinkPad X1 Yoga gen7 connects to the LG 27UL850-W monitor, the system experiences critical failures during boot processes where the PPM (Power Policy Manager) initialization fails with error code -110, indicating a timeout or resource acquisition failure. Additionally, the /sys/class/typec directory becomes empty, signifying that the Type-C subsystem has failed to properly enumerate connected devices, which can lead to complete loss of Type-C functionality including charging, data transfer, and display output capabilities. The vulnerability also triggers null pointer dereference errors that were previously fixed in the same code series, indicating that this timeout issue creates cascading failures that can compromise the entire USB Type-C subsystem. These failures manifest differently depending on when the monitor is connected - at boot time versus post-boot - but both scenarios result in complete loss of Type-C functionality. The vulnerability affects systems running Linux kernel versions that include the problematic ucsi_acpi driver implementation, particularly those using Type-C docks, monitors, and charging stations that require extended negotiation times for power delivery and display protocols.
The recommended mitigation for CVE-2023-53168 involves restoring the command completion timeout value from 1 second back to the original 5-second threshold, which effectively addresses the core timing issue without requiring system reboots or hardware modifications. This fix ensures that the USB Type-C subsystem has sufficient time to complete complex alternate mode discovery processes required by modern displays and docking solutions. System administrators should update to kernel versions that include the corrected timeout management, specifically targeting the commit that properly restores the 5-second timeout value after switching to polled mode. The mitigation strategy also includes monitoring Type-C device connections for error messages such as "PPM init failed (-110)" and "GET_CONNECTOR_STATUS failed (-110)" which serve as early warning indicators of this vulnerability. Organizations should prioritize updating their Linux systems, particularly those running enterprise or workstation environments where Type-C peripherals are commonly used, as the vulnerability can lead to complete system instability and data loss. Additionally, implementing proper error handling and logging for Type-C subsystem failures can help identify affected systems before complete functionality is lost, enabling proactive remediation rather than reactive troubleshooting. The fix addresses the fundamental timeout management issue while maintaining backward compatibility with existing Type-C device configurations and protocols.