CVE-2021-25931: Opennms Horizon

High severity, CVSS 8.8. EPSS: 0.7% chance of exploitation in the next 30 days.

In OpenNMS Horizon, versions opennms-1-0-stable through opennms-27.1.0-1; OpenNMS Meridian, versions meridian-foundation-2015.1.0-1 through meridian-foundation-2019.1.18-1; meridian-foundation-2020.1.0-1 through meridian-foundation-2020.1.6-1 are vulnerable to CSRF, due to no CSRF protection at `/opennms/admin/userGroupView/users/updateUser`. This flaw allows assigning `ROLE_ADMIN` security role to a normal user. Using this flaw, an attacker can trick the admin user to assign administrator privileges to a normal user by enticing him to click upon an attacker-controlled website.

Affected products

• Opennms Horizon: from 1.0, before 27.1.1 (fixed in 27.1.1)
• Opennms Meridian: from 2015.1.0, before 2019.1.19 (fixed in 2019.1.19); from 2020.1.0, before 2020.1.7 (fixed in 2020.1.7)

Published 2021-05-20. Last modified 2026-06-17.