CVE-2026-53759 in monitoring-plugins
Summary
by MITRE • 08/19/2026
linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations. Prior to version 4.2.0, db_sqlite.py created SQLite databases at predictable paths in the shared /tmp directory and followed attacker-created symbolic links at those paths. An attacker who controls a local monitoring account can create a symlink such as /tmp/linuxfabrik-monitoring-plugins-docker-stats.db and then trigger a sudo-authorized plugin, causing the root process to create or modify the symlink target. The primitive can overwrite arbitrary paths, cause denial of service, or manipulate an existing SQLite database through a crafted rollback journal or write-ahead log. The Monitoring Plugins integration also moved plugin caches through lib.db_sqlite.get_db_path() so they use the secured per-user directory. This issue is fixed in version 4.2.0.
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Analysis
by VulDB Data Team • 08/19/2026
The vulnerability identified in linuxfabrik-lib prior to version 4.2.0 represents a critical security flaw rooted in improper handling of temporary file creation and symbolic link resolution within shared system directories. The core technical deficiency lies in the implementation of db_sqlite.py, which was designed to create SQLite database files at predictable paths located within the /tmp directory. This directory is globally writable by all users on most Linux systems, making it a high-risk environment for race conditions and symlink attacks. By using static or easily guessable file names rather than secure temporary file creation mechanisms such as mkstemp with appropriate flags, the library exposed itself to manipulation by any local user who could access that specific directory path.
The operational impact of this flaw is severe due to its interaction with privilege escalation vectors within the monitoring infrastructure. An attacker possessing a low-privileged local account associated with the linuxfabrik-monitoring-plugins service can exploit this weakness through a classic symlink attack. By creating a symbolic link at the predictable location, such as /tmp/linuxfabrik-monitoring-plugins-docker-stats.db, pointing to an arbitrary file on the filesystem, the attacker sets a trap for higher-privileged processes. When a sudo-authorized plugin is triggered that utilizes db_sqlite.py to access or create this database, the root process follows the symbolic link and writes data into the target location specified by the attacker. This mechanism effectively allows a low-privilege user to write arbitrary content as the root user, bypassing standard file permission controls.
Beyond simple overwrites of configuration files or sensitive data, this vulnerability enables more sophisticated attacks involving SQLite-specific features. An adversary can manipulate an existing SQLite database through crafted rollback journals or write-ahead logs (WAL). These internal SQLite structures allow for complex state manipulations that could corrupt the integrity of critical monitoring databases or inject malicious payloads into system processes that rely on these files for operational data. Furthermore, if the symlink points to a non-existent file in a restricted directory, the root process may fail to create it due to permission denied errors, leading to application crashes and resulting in a denial of service condition for the monitoring services managed by linuxfabrik-lib.
This issue is classified under CWE-59 Improper Link Resolution Before File Access commonly known as a symlink race or TOCTOU vulnerability when timing is involved, though here it relies more on predictable naming conventions than strict time-of-check-to-time-of-use races. In terms of the MITRE ATT&CK framework, this behavior aligns with T1060 Privilege Escalation via Blinding Permissions and potentially T1548 Abuse Elevation Control Mechanism if sudo configurations are leveraged to execute the vulnerable code paths. The vulnerability highlights the dangers of relying on shared temporary directories for sensitive application state without enforcing strict ownership, permissions, or using secure file creation APIs that prevent symlink following during file generation.
The remediation strategy implemented in version 4.2.0 addresses these risks by altering how database and cache files are stored. Specifically, the Monitoring Plugins integration was updated to utilize lib.db_sqlite.get_db_path() which now directs storage to secured per-user directories rather than the global /tmp space. Per-user directories typically have restrictive permissions that prevent other users from creating symlinks or writing to them without explicit authorization. This change eliminates the attack surface by ensuring that only the intended user process can access its own database files, thereby neutralizing the ability of an attacker to redirect writes via symbolic links. Organizations running versions prior to 4.2.0 should upgrade immediately and audit their sudo configurations to ensure no other plugins or services are relying on similar insecure patterns for temporary file storage in shared directories.