An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated networked attacker to cause a Denial of Service (DoS) by sending specific packets over VXLAN which cause the PFE to reset. This issue affects: Juniper Networks Junos OS 19.4 versions prior to 19.4R3-S7; 20.1 versions prior to 20.1R3-S3; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S2; 20.4 versions prior to 20.4R3-S1; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R2; 21.3 versions prior to 21.3R1-S1, 21.3R2. This issue does not affect versions of Junos OS prior to 19.4R1.