CVE-2026-46170

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

mptcp: pm: ADD_ADDR rtx: free sk if last

When an ADDADDR is retransmitted, the sk is held in skreset_timer(), and released at the end.

If at that moment, it was the last reference being held, the sk would not be freed. sock_put() should then be called instead of _sockput().

But that's not enough: if it is the last reference, sockput() will call skfree(), which will end up calling skstoptimersync() on the same timer, and waiting indefinitely to finish. So it is needed to mark that the timer is done at the end of the timer handler when it has not been rescheduled, not to call skstoptimersync() on "itself".