CVE-2026-55426 PUBLISHED

linuxfabrik-lib: Local privilege escalation using embedded command

Assigner: GitHub_M
Reserved: 16.06.2026 Published: 18.08.2026 Updated: 18.08.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 7.8

Product Status

Vendor Linuxfabrik
Product monitoring-plugins
Versions
  • Version < 6.0.0 is affected
Vendor Linuxfabrik
Product lib
Versions
  • Version < 5.0.0 is affected

References

Problem Types

  • CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE