CVE-2021-25935: Opennms Horizon

Medium severity, CVSS 5.4. EPSS: 0.9% chance of exploitation in the next 30 days.

In OpenNMS Horizon, versions opennms-17.0.0-1 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-2020.1.7-1 are vulnerable to Stored Cross-Site Scripting, since the function `add()` performs improper validation checks on the input sent to the `foreign-source` parameter. Due to this flaw an attacker could bypass the existing regex validation and inject an arbitrary script which will be stored in the database.

Affected products

• Opennms Horizon: from 17.0.0, up to and including 27.1.0
• Opennms Meridian: from 2015.1.0, up to and including 2019.1.18; from 2020.1.0, up to and including 2020.1.7

Published 2021-05-25. Last modified 2026-06-17.