CVE-2026-23009CVE-2026-23009

In the Linux kernel, the following vulnerability has been resolved: xhci: sideband: don't dereference freed ring when removing sideband endpoint xhci_sideband_remove_endpoint() incorrecly assumes that the endpoint is running and has a valid transfer ring. Lianqin reported a crash during suspend/wake-up stress testing, and found the cause to be dereferencing a non-existing transfer ring 'ep->ring' during xhci_sideband_remove_endpoint(). The endpoint and its ring may be in unknown state if this function is called after xHCI was reinitialized in resume (lost power), or if device is being re-enumerated, disconnected or endpoint already dropped. Fix this by both removing unnecessary ring access, and by checking ep->ring exists before dereferencing it. Also make sure endpoint is running before attempting to stop it. Remove the xhci_initialize_ring_info() call during sideband endpoint removal as is it only initializes ring structure enqueue, dequeue and cycle state values to their start