Receipt of specially crafted UDP/IP packets over MPLS may be able to bypass a stateless firewall filter. The crafted UDP packets must be encapsulated and meet a very specific packet format to be classified in a way that bypasses IP firewall filter rules. The packets themselves do not cause a service interruption (e.g. RPD crash), but receipt of a high rate of UDP packets may be able to contribute to a denial of service attack. This issue only affects processing of transit UDP/IP packets over MPLS, received on an interface with MPLS enabled. TCP packet processing and non-MPLS encapsulated UDP packet processing are unaffected by this issue. Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D76; 12.3 versions prior to 12.3R12-S10; 12.3X48 versions prior to 12.3X48-D66, 12.3X48-D70; 14.1X53 versions prior to 14.1X53-D47; 15.1 versions prior to 15.1F6-S10, 15.1R4-S9, 15.1R6-S6, 15.1R7; 15.1X49 versions prior to 15.1X49-D131, 15.1X49-D140; 15.1X53 versions p…