This vulnerability (CVE-2026-33797) involves improper input validation (CWE-20) in Juniper Networks Junos OS and Junos OS Evolved, specifically in the handling of BGP packets. An unauthenticated attacker with adjacency to the target can send a crafted genuine BGP packet during an established BGP session to reset that session, resulting in a denial of service. The vulnerability affects Junos OS and Junos OS Evolved 25.2 versions prior to 25.2R2, impacting both eBGP and iBGP sessions over IPv4 and IPv6. The CVSS v3.1 score is 7.4, indicating high severity with attack vector as adjacent network, low attack complexity, no privileges required, no user interaction, and a scope change with impact limited to availability (DoS). No vendor advisory or patch information is currently available to confirm remediation status.

Successful exploitation causes a denial of service by resetting an established BGP session, disrupting network routing for affected sessions. This can degrade network availability and stability. There is no impact on confidentiality or integrity according to the CVSS vector. The vulnerability affects both internal and external BGP sessions over IPv4 and IPv6.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, network administrators should monitor BGP session stability and consider implementing network-level controls to restrict adjacency to trusted devices. No official remediation or temporary fix has been documented at this time.