CVE-2026-68161 sctp: close UDP tunnel sockets during netns teardown

In the Linux kernel, the following vulnerability has been resolved: sctp: close UDP tunnel sockets during netns teardown procsctpdoudpport starts per-net SCTP UDP tunneling sockets when net.sctp.udpport is set, and stops/restarts them when the sysctl value changes. The netns exit path does not st...