LibreNMS: Remote Code Execution by Signal Alert Transportation Module (CVE-2026-55182) | HOL Guard CVE

High severityCVE-2026-55182GHSA-C9FV-CGMM-2WG7

LibreNMS: Remote Code Execution by Signal Alert Transportation Module

Answer in brief

CVE-2026-55182 records a High severity vulnerability in LibreNMS: Remote Code Execution by Signal Alert Transportation Module. The current sources do not mark it as known exploited. The current feed maps librenms/librenms (composer), librenms/librenms (generic), librenms/librenms (packagist). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 26, 2026Updated Aug 26, 2026Source checked Aug 26, 2026First seen by HOL Aug 18, 2026Material review Aug 26, 2026

Upstream Advisory

Key facts

Risk: High
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps librenms/librenms (composer), librenms/librenms (generic), librenms/librenms (packagist). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
librenms/librenmscomposer	>=21.6.0,<26.5.0	26.5.0
librenms/librenmsgeneric	>= 21.6.0, < 26.5.0	Not reported
librenms/librenmspackagist	>=21.6.0 <26.5.0	26.5.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for librenms/librenms, librenms/librenms, librenms/librenms.
Review the reported fix. Update librenms/librenms to 26.5.0; librenms/librenms to 26.5.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 18, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.