CVE-2021-23133

A race condition in Linux kernel SCTP sockets (net/sctp/socket.c) before 5.12-rc8 can lead to kernel privilege escalation from the context of a network service or an unprivileged process. If sctpdestroysock is called without socknet(sk)->sctp.addrwqlock then an element is removed from the autoasconfsplist list without any proper locking. This can be exploited by an attacker with network service privileges to escalate to root or from the context of an unprivileged user directly if a BPFCGROUPINETSOCK_CREATE is attached which denies creation of some SCTP socket.