CVE-2026-23009

/// Technical description

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

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References