An Improper Validation of Syntactic Correctness of Input vulnerability in the Juniper DHCP daemon (jdhcpd) of Juniper Networks Junos OS allows an adjacent unauthenticated attacker sending a malformed DHCP packet to cause a crash of jdhcpd and thereby a Denial of Service (DoS). If option-82 is configured in a DHCP snooping / -security scenario, jdhcpd crashes if a specific malformed DHCP request packet is received. The DHCP functionality is impacted while jdhcpd restarts, and continued exploitation of the vulnerability will lead to the unavailability of the DHCP service and thereby a sustained DoS. This issue affects Juniper Networks Junos OS 13.2 version 13.2R1 and later versions prior to 15.1R7-S11; 18.3 versions prior to 18.3R3-S6; 18.4 versions prior to 18.4R2-S9, 18.4R3-S10; 19.1 versions prior to 19.1R2-S3, 19.1R3-S7; 19.2 versions prior to 19.2R1-S8, 19.2R3-S4; 19.3 versions prior to 19.3R2-S7, 19.3R3-S4; 19.4 versions prior to 19.4R3-S6; 20.1 versions prior to 20.1R3-S3; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S1; 20.4 versions prior to 20.4R3; 21.1 versions prior to 21.1R2-S1, 21.1R3; 21.2 versions prior to 21.2R1-S1, 21.2R2. This issue does not affect Juniper Networks Junos OS version 12.3R12 and prior versions.

A certain crafted HTTP packet can trigger an uninitialized function pointer deference vulnerability in the Packet Forwarding Engine manager (fxpc) on all EX, QFX and MX Series devices in a Virtual Chassis configuration. This issue can result in a crash of the fxpc daemon or may potentially lead to remote code execution. This issue only occurs when the crafted packet it destined to the device. Affected releases are Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D47 on EX and QFX Virtual Chassis Platforms; 15.1 versions prior to 15.1R7-S3 all Virtual Chassis Platforms 15.1X53 versions prior to 15.1X53-D50 on EX and QFX Virtual Chassis Platforms.

Juniper Junos OS before 13.2X51-D36, 14.1X53 before 14.1X53-D25, and 15.2 before 15.2R1 on EX4300 series switches allow remote attackers to cause a denial of service (network loop and bandwidth consumption) via unspecified vectors related to Spanning Tree Protocol (STP) traffic.