An Improper Input Validation vulnerability in the Juniper DHCP daemon (jdhcpd) of Juniper Networks Junos OS allows an adjacent unauthenticated attacker to cause a crash of jdhcpd and thereby a Denial of Service (DoS). If a device is configured as DHCPv6 local server and persistent storage is enabled jdhcpd will crash when receiving a specific DHCPv6 message. This issue affects: Juniper Networks Junos OS All versions prior to 15.1R7-S11; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R2-S3 19.1R3-S7; 19.2 versions prior to 19.2R1-S8 19.2R3-S3; 19.4 versions prior to 19.4R3-S5; 20.1 versions prior to 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3-S1; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2; 21.2 versions prior to 21.2R2.