CVE-2026-101993: CWE-617 Reachable Assertion in Juniper Networks Junos OS

This vulnerability (CVE-2026-101993) involves a reachable assertion failure in the routing protocol daemon (rpd) component of Juniper Networks Junos OS and Junos OS Evolved. An adjacent eBGP peer can trigger this vulnerability by sending a crafted VPLS signaling update when automatic site-ID negotiation is enabled, resulting in a denial of service condition. The issue is tracked under CWE-617 (Reachable Assertion). The vulnerability affects multiple specific versions of Junos OS and Junos OS Evolved as detailed in the affectedVersions field. The CVSS v3.1 base score is 6.5 with attack vector as adjacent network, low attack complexity, no privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, and high availability impact.

Successful exploitation allows an adjacent eBGP peer to cause a denial of service on the affected device by triggering a reachable assertion failure in the routing protocol daemon. This results in service disruption but does not impact confidentiality or integrity of the system.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Until a patch is available, consider disabling automatic site-ID negotiation if feasible or restricting adjacency with untrusted eBGP peers to reduce exposure.