CVE-2025-38268: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38268 is a vulnerability discovered in the Linux kernel affecting the USB Type-C Port Manager (TCPM) subsystem. The vulnerability was disclosed on July 10, 2025, and involves a potential deadlock condition in the tcpmqueuevdm_unlocked function when handling DisplayPort Alt Mode operations (NVD).

The vulnerability stems from an unprotected state check in tcpmqueuevdmunlocked that could lead to a deadlock scenario. Specifically, when the DisplayPort Alt Mode driver attempts to grab the tcpmlock while executing work, and simultaneously the TCPM holds the lock while trying to unregister the altmode, it can result in blocking on the altmode driver's cancelworksync call. The vulnerability creates a small window where the Alt Mode driver could determine the TCPM is in a ready state and attempt to grab the lock while the TCPM changes the state, causing a deadlock (NVD).

The vulnerability can result in a system deadlock when using USB Type-C DisplayPort Alt Mode functionality. This could potentially affect system stability and USB-C display connectivity, though no direct security implications have been reported (NVD).

The fix involves modifying tcpmqueuevdmunlocked to queue for tcpmqueuevdmwork, which performs the state check while holding the TCPM lock when the Alt Mode lock is no longer held. This required implementing a new struct called altmodevdmevent to hold the VDM data (NVD).