CVE-2026-55182 LibreNMS: Remote Code Execution by Signal Alert Transportation Module
An authenticated administrator can execute arbitrary OS commands on LibreNMS hosts via command injection in the Signal alert transport module.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55182?
CVE-2026-55182 is a high-severity command injection vulnerability in librenms, published on 26 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
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.
Weakness: CWE-77
Which versions are affected by CVE-2026-55182?
2 open source packages ship an affected version, including librenms/librenms.
| Package | Affected | Fixed in |
|---|---|---|
librenms/librenms Packagist | From 21.6.0 | 26.5.0 |
librenms/librenms Packagist | From 21.6.0 | 26.5.0 |
How do I fix CVE-2026-55182?
Upgrade librenms/librenms to 26.5.0 or later.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-55182 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55182 exists.
Sources
Also known as GHSA-c9fv-cgmm-2wg7.