Juniper Networks Junos OS uses the 128.0.0.0/2 subnet for internal communications between the RE and PFEs. It was discovered that packets utilizing these IP addresses may egress an EX4300 switch, leaking configuration information such as heartbeats, kernel versions, etc. out to the Internet, leading to an information exposure vulnerability. This issue affects Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D53 on EX4300; 15.1 versions prior to 15.1R7-S6 on EX4300; 15.1X49 versions prior to 15.1X49-D200, 15.1X49-D210 on EX4300; 16.1 versions prior to 16.1R7-S7 on EX4300; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2 on EX4300; 17.2 versions prior to 17.2R3-S3 on EX4300; 17.3 versions prior to 17.3R2-S5, 17.3R3-S7 on EX4300; 17.4 versions prior to 17.4R2-S9, 17.4R3 on EX4300; 18.1 versions prior to 18.1R3-S8 on EX4300; 18.2 versions prior to 18.2R3-S2 on EX4300; 18.3 versions prior to 18.3R2-S3, 18.3R3, 18.3R3-S1 on EX4300; 18.4 versions prior to 18.4R1-S5, 18.4R2-S3, 18.4R3 on EX4300; 19.1 versions prior to 19.1R1-S4, 19.1R2 on EX4300; 19.2 versions prior to 19.2R1-S4, 19.2R2 on EX4300; 19.3 versions prior to 19.3R1-S1, 19.3R2 on EX4300.