CVE-2021-25933: Opennms Horizon

Medium severity, CVSS 4.8. EPSS: 1% 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 Stored Cross-Site Scripting, since the function `validateFormInput()` performs improper validation checks on the input sent to the `groupName` and `groupComment` parameters. Due to this flaw, an authenticated attacker could inject arbitrary script and trick other admin users into downloading malicious files which can cause severe damage to the organization using opennms.

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.