A vulnerability in Handling of Undefined Values in the routing protocol daemon (RPD) process of Juniper Networks Junos OS and Junos OS Evolved may allow an unauthenticated network-based attacker to crash the RPD process by sending a specific BGP update while the system is under heavy load, leading to a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. Malicious exploitation of this issue requires a very specific combination of load, timing, and configuration of the vulnerable system which is beyond the direct control of the attacker. Internal reproduction has only been possible through artificially created load and specially instrumented source code. Systems are only vulnerable to this issue if BGP multipath is enabled. Routers not configured for BGP multipath are not vulnerable to this issue. This issue affects: Juniper Networks Junos OS: 21.1 versions prior to 21.1R3-S1.

21.2 versions prior to 21.2R2-S2, 21.2R3.

21.3 versions prior to 21.3R2, 21.3R3.

21.4 versions prior to 21.4R1-S1, 21.4R2. Juniper Networks Junos OS Evolved: 21.1 versions prior to 21.1R3-S1-EVO.

21.2 version 21.2R1-EVO and later versions.

21.3 versions prior to 21.3R3-EVO.

21.4 versions prior to 21.4R1-S1-EVO, 21.4R2-EVO. This issue does not affect: Juniper Networks Junos OS versions prior to 21.1. Juniper Networks Junos OS Evolved versions prior to 21.1-EVO.