---
id: CVE-2026-55426
title: >-
  linuxfabrik-lib provides Python modules for database access, caching, shell
  execution, and API integrations, and Linuxfabrik Monitoring Plugins uses those
  modules to run external monitoring commands
summary: >-
  linuxfabrik-lib provides Python modules for database access, caching, shell
  execution, and API integrations, and Linuxfabrik Monitoring Plugins uses those
  modules to run external monitoring commands. From the earliest affected
  releases u…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
vendor: linuxfabrik-lib
product: linuxfabrik-lib
affected:
  - linuxfabrik-lib < 5.0.0
patched:
  - linuxfabrik-lib 5.0.0
published: '2026-08-18'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:13:25.910'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55426'
references:
  - url: 'https://github.com/Linuxfabrik/lib/blob/main/CHANGELOG.md'
    label: security-advisories@github.com
  - url: 'https://github.com/Linuxfabrik/lib/releases/tag/v5.0.0'
    label: security-advisories@github.com
  - url: 'https://github.com/Linuxfabrik/monitoring-plugins/blob/main/CHANGELOG.md'
    label: security-advisories@github.com
  - url: >-
      https://github.com/Linuxfabrik/monitoring-plugins/commit/23bb570f41fc8d9caf30b30074bba0e3db1b357a
    label: security-advisories@github.com
  - url: 'https://github.com/Linuxfabrik/monitoring-plugins/releases/tag/v6.0.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/Linuxfabrik/monitoring-plugins/security/advisories/GHSA-798h-hpph-m24j
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-798h-hpph-m24j'
tags:
  - nvd
  - ghsa
  - pip
epss: 0.00211
epssPercentile: 0.1009
aliases:
  - GHSA-798h-hpph-m24j
ecosystem: pip
ingestedAt: '2026-07-06T21:45:52.941Z'
---

## Overview

linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations, and Linuxfabrik Monitoring Plugins uses those modules to run external monitoring commands. From the earliest affected releases until linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0, check plugins embedded user-controlled values in command strings passed to lib.shell.shell_exec(), which split strings at pipe characters and executed the resulting commands. In check-plugins/restic-check/restic-check, the --repo parameter could inject a pipe-delimited command into a constructed restic invocation, and sudo-authorized execution allowed a compromised nagios or icinga account to run that command as root. The shared library also accepted command strings and a shell parameter, while numerous plugins constructed external commands from attacker-influenced arguments. The fixes require argv lists, always use shell=False, remove pipe splitting, and reject option-like positional values through lib.shell.safe_cli_value(). These issues are fixed in linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-55426)

Affected packages:

- `linuxfabrik-lib < 5.0.0`

Patched in:

- `linuxfabrik-lib 5.0.0`

Source: https://github.com/advisories/GHSA-798h-hpph-m24j