Affected: Juniper Networks Junos OS, Juniper Networks Junos OS Evolved

An Improper Input Validation vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent attacker to cause a PFE crash and thereby a Denial of Service (DoS). An FPC will crash and reboot after receiving a specific transit IPv6 packet over MPLS. Continued receipt of this packet will create a sustained Denial of Service (DoS) condition. This issue does not affect systems configured for IPv4 only. This issue affects: Juniper Networks Junos OS All versions prior to 12.3R12-S21; 15.1 versions prior to 15.1R7-S10; 17.3 versions prior to 17.3R3-S12; 18.3 versions prior to 18.3R3-S6; 18.4 versions prior to 18.4R2-S9, 18.4R3-S9; 19.1 versions prior to 19.1R2-S3, 19.1R3-S7; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S7, 19.3R3-S4; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2-S2, 20.4R3; 21.1 versions prior to 21.1R2. Juniper Networks Junos OS Evolved All versions prior to 20.4R3-S3-EVO; 21.2 versions prior to 21.2R3-EVO; 21.3 versions prior to 21.3R2-S1-EVO, 21.3R3-EVO; 21.4 versions prior to 21.4R2-EVO.