Critical Unauthenticated RCE Vulnerability in Juniper Networks PTX Series Routers
In February 2026, Juniper Networks disclosed a critical vulnerability (CVE-2026-21902) in its Junos OS Evolved operating system running on PTX Series routers. This flaw, stemming from incorrect permission assignments in the On-Box Anomaly Detection framework, allows unauthenticated, network-based attackers to execute code with root privileges. The vulnerability affects Junos OS Evolved versions prior to 25.4R1-S1-EVO and 25.4R2-EVO, potentially leading to full device compromise. The exposure of such a critical service over externally accessible ports underscores the importance of rigorous access controls and timely patch management. Organizations relying on PTX Series routers should prioritize applying the provided patches or implementing recommended mitigations to prevent potential exploitation.
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