net/sctp/sm_sideeffect.c in the Linux kernel before 4.3 does not properly manage the relationship between a lock and a socket, which allows local users to cause a denial of service (deadlock) via a crafted sctp_accept call.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.