CVE-2026-55182: Librenms

High severity, CVSS 8.6. EPSS: 1.6% chance of exploitation in the next 30 days.

LibreNMS is a network monitoring system. In versions from 21.6.0 up to 26.5.0, the Signal alert transport is vulnerable to command injection because the signal-cli path and the Recipient field of an alert transport entry are insufficiently escaped before being passed to an exec call. An authenticated administrator can craft a transport entry whose Recipient contains shell metacharacters and whose path points to the bundled composer_wrapper.php script, which itself passes attacker-controlled input to further unsafe exec calls. By chaining these calls, the administrator can execute arbitrary operating-system commands on the LibreNMS host. This issue is fixed in version 26.5.0.

Affected products

• Librenms Librenms: from 21.6.0, before 26.5.0 (fixed in 26.5.0)

Published 2026-08-26. Last modified 2026-09-09.