This vulnerability (CVE-2026-33801) involves an improper check for unusual or exceptional conditions (CWE-754) in the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved. An attacker adjacent to the device can send a malformed non-inet/inet6 unicast BGP update over an established BGP session, causing the RPD process to crash and restart. This results in a denial-of-service condition due to service outage until routing reconvergence. The crash occurs before the update can be propagated downstream, limiting the impact to the affected device. The affected versions are Junos OS 25.2 prior to 25.2R2 and Junos OS Evolved 25.2 prior to 25.2R2-EVO. Earlier versions before 25.2R1 are not vulnerable. No official patch or remediation level has been stated in the provided data.

An adjacent unauthenticated attacker can cause the routing protocol daemon (RPD) to crash and restart by sending a specially crafted BGP update. This leads to a denial-of-service condition on the affected device, causing a complete service outage until routing reconverges. There is no impact on confidentiality or integrity, and no downstream propagation of the malformed update occurs.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or remediation level has been provided in the available data. Until a patch is available, network administrators should consider limiting BGP session adjacency to trusted peers and monitor for unusual BGP update activity. Avoid exposure of BGP sessions to untrusted or unauthenticated sources.