Insufficient validation of environment variables in the telnet client supplied in Junos OS can lead to stack-based buffer overflows, which can be exploited to bypass veriexec restrictions on Junos OS. A stack-based overflow is present in the handling of environment variables when connecting via the telnet client to remote telnet servers. This issue only affects the telnet client — accessible from the CLI or shell — in Junos OS. Inbound telnet services are not affected by this issue. This issue affects: Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S13; 12.3X48 versions prior to 12.3X48-D80; 14.1X53 versions prior to 14.1X53-D130, 14.1X53-D49; 15.1 versions prior to 15.1F6-S12, 15.1R7-S4; 15.1X49 versions prior to 15.1X49-D170; 15.1X53 versions prior to 15.1X53-D237, 15.1X53-D496, 15.1X53-D591, 15.1X53-D69; 16.1 versions prior to 16.1R3-S11, 16.1R7-S4; 16.2 versions prior to 16.2R2-S9; 17.1 versions prior to 17.1R3; 17.2 versions prior to 17.2R1-S8, 17.2R2-S7, 17.2R3-S1; 17.3 versions prior to 17.3R3-S4; 17.4 versions prior to 17.4R1-S6, 17.4R2-S3, 17.4R3; 18.1 versions prior to 18.1R2-S4, 18.1R3-S3; 18.2 versions prior to 18.2R1-S5, 18.2R2-S2, 18.2R3; 18.2X75 versions prior to 18.2X75-D40; 18.3 versions prior to 18.3R1-S3, 18.3R2; 18.4 versions prior to 18.4R1-S2, 18.4R2.

The srxpfe process may crash on SRX Series services gateways when the UTM module processes a specific fragmented HTTP packet. The packet is misinterpreted as a regular TCP packet which causes the processor to crash. This issue affects all SRX Series platforms that support URL-Filtering and have web-filtering enabled. Affected releases are Juniper Networks Junos OS: 12.3X48 versions prior to 12.3X48-D85 on SRX Series; 15.1X49 versions prior to 15.1X49-D181, 15.1X49-D190 on SRX Series; 17.3 versions on SRX Series; 17.4 versions prior to 17.4R1-S8, 17.4R2-S5, 17.4R3 on SRX Series; 18.1 versions prior to 18.1R3-S6 on SRX Series; 18.2 versions prior to 18.2R2-S1, 18.2R3 on SRX Series; 18.3 versions prior to 18.3R1-S2, 18.3R2 on SRX Series; 18.4 versions prior to 18.4R1-S1, 18.4R2 on SRX Series.

When configuring a stateless firewall filter in Junos OS, terms named using the format "internal-n" (e.g. "internal-1", "internal-2", etc.) are silently ignored. No warning is issued during configuration, and the config is committed without error, but the filter criteria will match all packets leading to unexpected results. Affected releases are Juniper Networks Junos OS: All versions prior to and including 12.3; 14.1X53 versions prior to 14.1X53-D130, 14.1X53-D49; 15.1 versions prior to 15.1F6-S12, 15.1R7-S4; 15.1X49 versions prior to 15.1X49-D161, 15.1X49-D170; 15.1X53 versions prior to 15.1X53-D236, 15.1X53-D496, 15.1X53-D69; 16.1 versions prior to 16.1R7-S4, 16.1R7-S5; 16.2 versions prior to 16.2R2-S9; 17.1 versions prior to 17.1R3; 17.2 versions prior to 17.2R1-S8, 17.2R3-S1; 17.3 versions prior to 17.3R3-S4; 17.4 versions prior to 17.4R1-S7, 17.4R2-S3; 18.1 versions prior to 18.1R2-S4, 18.1R3-S4; 18.2 versions prior to 18.2R1-S5, 18.2R2-S1; 18.2X75 versions prior to 18.2X75-D40; 18.3 versions prior to 18.3R1-S3; 18.4 versions prior to 18.4R1-S1, 18.4R1-S2.

When BGP tracing is enabled an incoming BGP message may cause the Junos OS routing protocol daemon (rpd) process to crash and restart. While rpd restarts after a crash, repeated crashes can result in an extended DoS condition. Affected releases are Juniper Networks Junos OS: 16.1 versions prior to 16.1R7-S4, 16.1R7-S5; 16.2 versions prior to 16.2R2-S9, 16.2R3; 17.1 versions prior to 17.1R3; 17.2 versions prior to 17.2R3-S1; 17.3 versions prior to 17.3R3-S3, 17.3R3-S4, 17.3R4; 17.4 versions prior to 17.4R1-S7, 17.4R2-S3, 17.4R2-S4, 17.4R3; 18.1 versions prior to 18.1R2-S4, 18.1R3-S4, 18.1R4; 18.2 versions prior to 18.2R2-S2, 18.2R2-S3, 18.2R3; 18.2X75 versions prior to 18.2X75-D40; 18.3 versions prior to 18.3R1-S3, 18.3R2; 18.4 versions prior to 18.4R1-S2, 18.4R2. This issue does not affect Junos releases prior to 16.1R1.

Memory leak in Juniper JUNOS Packet Forwarding Engine (PFE) allows remote attackers to cause a denial of service (memory exhaustion and device reboot) via certain IPv6 packets.

TCP, when using a large Window Size, makes it easier for remote attackers to guess sequence numbers and cause a denial of service (connection loss) to persistent TCP connections by repeatedly injecting a TCP RST packet, especially in protocols that use long-lived connections, such as BGP.