An Improper Check for Unusual or Exceptional Conditions vulnerability in the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based attacker to cause a Denial of Service (DoS).  In a scenario where BGP Monitoring Protocol (BMP) is configured with rib-in pre-policy monitoring, receiving a BGP update with a specifically malformed AS PATH attribute over an established BGP session, can cause an RPD crash and restart. This issue affects: Junos OS:  * All versions before 21.2R3-S8, * 21.4 versions before 21.4R3-S8, * 22.2 versions before 22.2R3-S4, * 22.3 versions before 22.3R3-S3, * 22.4 versions before 22.4R3-S2, * 23.2 versions before 23.2R2-S1, * 23.4 versions before 23.4R1-S2, 23.4R2; Junos OS Evolved: * All versions before 21.2R3-S8-EVO, * 21.4 versions before 21.4R3-S8-EVO, * 22.2 versions before 22.2R3-S4-EVO, * 22.3 versions before 22.3R3-S3-EVO, * 22.4 versions before 22.4R3-S2-EVO, * 23.2 versions before 23.2R2-S1-EVO, * 23.4 versions before 23.4R1-S2-EVO, 23.4R2-EVO.