LibreNMS up to 26.4.x Signal composer_wrapper.php Recipient os command injection

Summaryinfo

A vulnerability, which was classified as problematic, was found in LibreNMS up to 26.4.x. The affected element is an unknown function of the file composer_wrapper.php of the component Signal. The manipulation of the argument Recipient results in os command injection. This vulnerability is identified as CVE-2026-55182. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in LibreNMS up to 26.4.x. It has been classified as problematic. Affected is some unknown functionality of the file composer_wrapper.php of the component Signal. The manipulation of the argument Recipient with an unknown input leads to a os command injection vulnerability. CWE is classifying the issue as CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-55182 since 06/16/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation needs additional levels of successful authentication. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1202 by the MITRE ATT&CK project.

By approaching the search of inurl:composer_wrapper.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 26.5.0 eliminates this vulnerability.

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Productinfo

Name

• LibreNMS

Version

• 26.0
• 26.1
• 26.2
• 26.3
• 26.4

License

• open-source

Website

• Product: https://github.com/librenms/librenms/

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