CVE-2025-52963 is an Improper Access Control vulnerability (CWE-284) identified in the User Interface (UI) of Juniper Networks Junos OS. This vulnerability allows a local attacker with low privileges—specifically users granted only "view" permissions—to execute a particular "request interface" command that can shut down network interfaces. This effectively enables the attacker to cause a Denial-of-Service (DoS) condition by bringing down critical network interfaces, disrupting network connectivity and operations. The vulnerability affects multiple versions of Junos OS, including all versions before 21.2R3-S9, and various subsequent releases up to 24.4R2, indicating a broad range of affected deployments. The CVSS v3.1 base score is 5.5 (medium severity), with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, meaning the attack requires local access and low privileges, no user interaction, and results in high impact on availability but no impact on confidentiality or integrity. No known exploits are currently reported in the wild, but the vulnerability’s nature makes it a significant risk in environments where multiple users have view-level access to Junos OS devices. The root cause is insufficient access control in the UI command execution, allowing users with limited permissions to perform disruptive actions beyond their intended scope.

For European organizations, this vulnerability poses a significant risk to network infrastructure stability and availability. Juniper Networks Junos OS is widely used in enterprise, telecommunications, and service provider networks across Europe. An attacker exploiting this flaw could disrupt critical network interfaces, leading to partial or full network outages. This can affect business continuity, especially for organizations relying on Juniper devices for core routing and switching functions. The impact is particularly severe for sectors with stringent uptime requirements such as finance, healthcare, government, and critical infrastructure. Since the attack requires only low-privileged local access, insider threats or compromised user accounts with view permissions could be leveraged to cause disruption. The lack of confidentiality or integrity impact reduces the risk of data breaches but does not diminish the operational impact of service unavailability. Additionally, network outages could cascade, affecting connected systems and services, potentially causing broader operational and reputational damage.

To mitigate this vulnerability, European organizations should take the following specific actions: 1) Immediately audit and restrict the assignment of "view" permissions in Junos OS to only trusted personnel, minimizing the number of users with any level of access to the UI. 2) Apply the latest Junos OS patches and updates as soon as they become available from Juniper Networks, ensuring that affected versions are upgraded to fixed releases beyond 21.2R3-S9, 21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, or 24.4R1-S3/24.4R2. 3) Implement strict network segmentation and access controls to limit local access to Junos OS devices, preventing unauthorized users from reaching the UI. 4) Monitor and log all interface shutdown commands and unusual UI activity to detect potential exploitation attempts early. 5) Employ multi-factor authentication and enhanced user session controls for device management interfaces to reduce the risk of compromised credentials being used. 6) Conduct regular security training for network administrators and users with access to Junos OS devices to raise awareness about privilege misuse risks. 7) Consider deploying intrusion detection or prevention systems that can identify anomalous command execution patterns on network devices.