CVE-2026-52929

In the Linux kernel, the following vulnerability has been resolved:

sctp: stream: fully roll back denied add-stream state

When ADD_OUT_STREAMS is denied, SCTP only shrinks the queued chunks and

then lowers outcnt. That leaves removed stream metadata behind, so a

later re-add can reuse a stale ext and hit a null-pointer dereference in

the scheduler get path.

Fix the rollback by tearing down the removed stream state the same way

other stream resizes do. Unschedule the current scheduler state, drop

the removed stream ext state with sctp_stream_outq_migrate(), and then

reschedule the remaining streams.

This keeps scheduler-private RR/FC/PRIO lists consistent while fully

rolling back denied outgoing stream additions.