An Improper Update of Reference Count vulnerability in the kernel of Juniper Networks Junos OS Evolved allows an unauthenticated network-based attacker to trigger a counter overflow eventually causing a Denial of Service (DoS). This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.4R3-S1-EVO; 21.1 versions prior to 21.1R3-EVO; 21.2 versions prior to 21.2R3-EVO; 21.3 versions prior to 21.3R2-EVO. This issue does not affect Juniper Networks Junos OS.