An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on EX4300 Series allows a locally authenticated attacker with low privileges to cause a Denial-of-Service (Dos). If a specific CLI command is issued, a PFE crash will occur. This will cause traffic forwarding to be interrupted until the system self-recovers. This issue affects Junos OS: All versions before 20.4R3-S10, 21.2 versions before 21.2R3-S7, 21.4 versions before 21.4R3-S6.