An Improper Control of a Resource Through its Lifetime vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows unauthenticated adjacent attacker to cause a Denial of Service (DoS). In an EVPN-MPLS scenario, if MAC is learned locally on an access interface but later a request to delete is received indicating that the MAC was learnt remotely, this can lead to memory corruption which can result in line card crash and reload. This issue affects: Juniper Networks Junos OS All versions 17.3R1 and later versions prior to 19.2R3-S5; 19.3 versions prior to 19.3R3-S5; 19.4 versions prior to 19.4R2-S6, 19.4R3-S8; 20.1 version 20.1R1 and later versions; 20.2 versions prior to 20.2R3-S4; 20.3 versions prior to 20.3R3-S3; 20.4 versions prior to 20.4R3-S3; 21.1 versions prior to 21.1R3-S1; 21.2 versions prior to 21.2R3; 21.3 versions prior to 21.3R2; 21.4 versions prior to 21.4R1-S1, 21.4R2. Juniper Networks Junos OS Evolved All versions prior to 20.4R3-S3-EVO; 21.1-EVO version 21.1R1-EVO and later versions; 21.2-EVO versions prior to 21.2R3-EVO; 21.3-EVO versions prior to 21.3R2-EVO; 21.4-EVO versions prior to 21.4R1-S1-EVO, 21.4R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 17.3R1.