A Improper Validation of Specified Index, Position, or Offset in Input 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). In a scenario where DHCP relay or local server is configured the problem can be triggered if a DHCPv4 packet with specific options is received leading to a corruption of the options read from the packet. This corruption can then lead to jdhcpd crash and restart. This issue affects: Juniper Networks Junos OS 17.4R1 and later versions prior to 18.4R3-S10; 19.1 versions prior to 19.1R3-S7; 19.2 versions prior to 19.2R1-S8, 19.2R3-S4; 19.3 versions prior to 19.3R3-S4; 19.4 versions prior to 19.4R3-S6; 20.1 versions prior to 20.1R3-S2; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S2; 20.4 versions prior to 20.4R3-S1; 21.1 versions prior to 21.1R2-S2, 21.1R3; 21.2 versions prior to 21.2R1-S2, 21.2R2, 21.2R3; 21.3 versions prior to 21.3R1-S1, 21.3R2.