CVE-2026-55426
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
Vulnerability in linuxfabrik-lib and Linuxfabrik Monitoring Plugins. 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 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.
Risk Assessment
Risk includes execution of arbitrary commands as root by a compromised monitoring account, potentially leading to full system compromise and integrity violation of monitored infrastructure.
Recommendation
Upgrade linuxfabrik-lib to version 5.0.0 or later and Linuxfabrik Monitoring Plugins to version 6.0.0 or later. Restrict sudo privileges for monitoring accounts.
Other vulnerabilities in linuxfabrik-lib
See all- CVE-2026-73974Medium
Vulnerability in linuxfabrik-lib and Linuxfabrik Monitoring Plugins allows reading files via a hidden --test argument that does not confine paths to the test directory. An attacker controlling the nagios or icinga account can disclose root-readable file contents, e.g., via the deb-updates plugin.
- CVE-2026-53759Low
Vulnerability in linuxfabrik-lib before version 4.2.0. The db_sqlite.py module created SQLite databases at predictable paths in /tmp and followed attacker-created symbolic links. An attacker with a local monitoring account can create a symlink and trigger a sudo-authorized plugin, leading to arbitrary path overwrite, denial of service, or manipulation of an existing database. Fixed in version 4.2.0.
- CVE-2026-67435Medium
A vulnerability in linuxfabrik-lib before version 6.0.0 allows a redirecting server to intercept credential headers (other than Authorization and Cookie) during URL requests. The lib.url.fetch() function forwards headers on cross-origin redirects.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS