An Uncontrolled Resource Consumption vulnerability in the handling of IPv6 neighbor state change events in Juniper Networks Junos OS allows an adjacent attacker to cause a memory leak in the Flexible PIC Concentrator (FPC) of an ACX5448 router. The continuous flapping of an IPv6 neighbor with specific timing will cause the FPC to run out of resources leading to a Denial of Service (DoS) condition. Once the condition occurs further packet processing will be impacted creating a sustained Denial of Service (DoS) condition requiring a manual PFE restart to restore service. The following error messages will be seen after the FPC resources have been exhausted: fpc0 DNX_NH::dnx_nh_tag_ipv4_hw_install() 3135: dnx_nh_tag_ipv4_hw_install: BCM L3 Egress create object failed for NH 602 (-14:No resources for operation) BCM NH Params: unit:0 Port:41 L3_INTF:0 Flags: 0x40 fpc0 DNX_NH::dnx_nh_tag_ipv4_hw_install() 3135: dnx_nh_tag_ipv4_hw_install: BCM L3 Egress create object failed for NH 602 (-14:No resources for operation) BCM NH Params: unit:0 Port:41 L3_INTF:0 Flags: 0x40 fpc0 DNX_NH::dnx_nh_tag_ipv4_hw_install() 3135: dnx_nh_tag_ipv4_hw_install: BCM L3 Egress create object failed for NH 602 (-14:No resources for operation) BCM NH Params: unit:0 Port:41 L3_INTF:0 Flags: 0x40 fpc0 DNX_NH::dnx_nh_tag_ipv4_hw_install() 3135: dnx_nh_tag_ipv4_hw_install: BCM L3 Egress create object failed for NH 602 (-14:No resources for operation) BCM NH Params: unit:0 Port:41 L3_INTF:0 Flags: 0x40 This issue only affects the ACX5448 router. No other products or platforms are affected by this vulnerability. This issue affects Juniper Networks Junos OS on ACX5448: 18.4 versions prior to 18.4R3-S10; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R1-S8 19.2R3-S2; 19.3 versions prior to 19.3R2-S6 19.3R3-S2; 19.4 versions prior to 19.4R1-S3 19.4R2-S2 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R1-S1 20.2R2.