CVE-2026-101977: CWE-476 NULL Pointer Dereference in Juniper Networks Junos OS

This vulnerability (CVE-2026-101977) involves a NULL Pointer Dereference in the routing protocol daemon (rpd) component of Juniper Networks Junos OS and Junos OS Evolved. A configured eBGP peer can exploit this flaw by sending a crafted BGP packet when ephemeral configuration is enabled, causing the routing daemon to crash and resulting in a persistent denial of service. The issue affects multiple version ranges across both Junos OS and Junos OS Evolved, including specific subversions and extended versions. The CVSS v3.1 base score is 7.5 with vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low attack complexity, no privileges or user interaction required, unchanged scope, no confidentiality or integrity impact, but high impact on availability.

Successful exploitation results in a persistent denial of service of the routing daemon (rpd), disrupting routing functionality on affected Junos OS and Junos OS Evolved devices. There is no impact on confidentiality or integrity reported. The disruption can affect network availability and stability.

Patch status is not yet confirmed — check the Juniper Networks vendor advisory for current remediation guidance. Since no patch links are provided in the input data, users should monitor official Juniper advisories for updates. Until a patch is applied, consider restricting or monitoring eBGP peer connections and ephemeral configuration usage to reduce exposure.