CVE-2021-23133
MediumCVSS 6.7Exploitation Probability (EPSS)
Low risk38th percentile - higher than 38% of all known CVEs
Summary
A race condition in the Linux kernel SCTP sockets implementation (net/sctp/socket.c) before version 5.12-rc8. If sctp_destroy_sock is called without the addr_wq_lock, an element is removed from the auto_asconf_splist list without proper locking. This can be exploited by an attacker with network service privileges to escalate to root or by an unprivileged user if a BPF_CGROUP_INET_SOCK_CREATE is attached that blocks creation of some SCTP sockets.
Risk Assessment
Risk of privilege escalation in the Linux kernel, potentially leading to full system compromise by an attacker with limited privileges.
Recommendation
Immediately update the Linux kernel to version 5.12-rc8 or later, which includes a fix for this vulnerability.
Original NVD description (English source)
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 sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock then an element is removed from the auto_asconf_splist 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 BPF_CGROUP_INET_SOCK_CREATE is attached which denies creation of some SCTP socket.