An Improper Handling of Missing Values vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an adjacent, unauthenticated attacker to cause a dcpfe process core and thereby a Denial of Service (DoS). Continued receipt of these specific frames will cause a sustained Denial of Service condition. This issue occurs when a specific malformed ethernet frame is received. This issue affects Juniper Networks Junos OS on QFX10000 Series, PTX1000 Series Series: All versions prior to 19.4R3-S10; 20.1 version 20.1R1 and later versions; 20.2 versions prior to 20.2R3-S6; 20.3 versions prior to 20.3R3-S6; 20.4 versions prior to 20.4R3-S5; 21.1 versions prior to 21.1R3-S4; 21.2 versions prior to 21.2R3-S3; 21.3 versions prior to 21.3R3-S3; 21.4 versions prior to 21.4R3-S1; 22.1 versions prior to 22.1R2-S1, 22.1R3; 22.2 versions prior to 22.2R1-S2, 22.2R2.