CVE-2026-101984: CWE-617 Reachable Assertion in Juniper Networks Junos OS

This vulnerability (CVE-2026-101984) involves a reachable assertion in the routing protocol daemon (rpd) component of Juniper Networks Junos OS and Junos OS Evolved. When the labeled-unicast aggregate-label configuration is enabled, a network-adjacent BGP peer can trigger this assertion, resulting in a denial of service condition. The vulnerability affects a range of versions across both Junos OS and Junos OS Evolved, including specific release trains and extended versions. The CVSS 3.1 base score is 6.5 with attack vector as adjacent network, low attack complexity, no privileges required, no user interaction, and impact limited to availability. There is no indication of confidentiality or integrity impact. No vendor advisory or patch links were provided, so patch status is not confirmed.

An attacker with network adjacency and BGP peer capabilities can cause a denial of service on affected Junos OS devices by triggering the reachable assertion in the routing protocol daemon. This disrupts availability but does not affect confidentiality or integrity of the system. No known exploits are reported in the wild.

Patch status is not yet confirmed — check the Juniper Networks vendor advisory for current remediation guidance. Until an official fix is available, consider disabling the labeled-unicast aggregate-label configuration if feasible or restricting BGP peer access to trusted entities to reduce exposure.