CVE-2026-101976: CWE-787 Out-of-bounds Write in Juniper Networks Junos OS

This vulnerability (CVE-2026-101976) involves an out-of-bounds write in the routing protocol daemon (rpd) component of Juniper Networks Junos OS and Junos OS Evolved. An eBGP peer lacking the four-octet-AS capability can send a malformed BGP update that triggers this flaw, resulting in a denial-of-service (DoS) condition. The issue affects a range of Junos OS and Junos OS Evolved versions prior to certain service releases as detailed in the affectedVersions field. The CVSS v3.1 base score is 7.5, reflecting a high severity impact primarily due to availability disruption. No vendor patch or fix information is included in the input, and no known exploits have been observed in the wild.

Successful exploitation causes a denial-of-service (DoS) condition in the routing protocol daemon (rpd) of Junos OS and Junos OS Evolved, disrupting network routing services. There is no impact on confidentiality or integrity reported. The vulnerability requires network attacker capability (remote, no privileges, no user interaction).

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, network administrators should consider restricting or monitoring eBGP peers that have not negotiated the four-octet-AS capability to mitigate potential exploitation.