CVE-2026-17548 in Checkmk
Summary
by MITRE • 08/25/2026
Missing authorization in Checkmk <2.5.0p12, <2.4.0p36, <2.3.0p50 and all 2.2.0 versions allows an authenticated user who knows the ID of a background job to view that job's status and results.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified in Checkmk versions prior to 2.5.0p12, 2.4.0p36, 2.3.0p50, and all releases within the 2.2.0 branch represents a critical failure in access control mechanisms for background job management interfaces. This flaw specifically affects authenticated users who possess knowledge of specific internal identifiers associated with ongoing or completed system tasks. In typical enterprise monitoring environments such as those managed by Checkmk, administrators and operators frequently initiate long-running operations like site updates, configuration imports, or performance data processing. These processes are tracked via unique background job IDs that serve as handles for retrieving status updates and final results through the web interface API.
The core technical flaw lies in the absence of proper authorization checks when querying these job details. While the system correctly verifies that a user is authenticated to access the application, it fails to validate whether that specific user has permission to view the metadata or output associated with a particular background job ID. This oversight allows any logged-in account, regardless of its privilege level within the Checkmk hierarchy, to iterate through sequential or guessed job identifiers and retrieve sensitive information. The vulnerability essentially transforms an internal operational mechanism into a data exfiltration vector for lower-privileged users who might otherwise have restricted views on system administration activities.
From an impact perspective, this unauthorized access can lead to significant security implications beyond simple information disclosure. An attacker with low-level privileges could monitor the progress of administrative tasks such as software patches or configuration changes. By observing job statuses and results, they may infer details about the organization's infrastructure topology, patch levels, installed plugins, or specific configurations being applied. This intelligence gathering can facilitate further attacks by revealing system weaknesses or identifying windows of opportunity during maintenance periods when systems might be temporarily vulnerable or restarted. Additionally, if job outputs contain sensitive data such as error logs with internal IP addresses or database connection strings, the confidentiality integrity and availability aspects of security are compromised.
This vulnerability aligns closely with Common Weakness Enumeration category CWE-284, which describes Improper Access Control where a user is able to access resources they should not be permitted to view. It also maps to MITRE ATT&CK technique T1078, Valid Accounts, as the exploitation relies on legitimate authentication credentials combined with lateral movement or privilege escalation through information gathering rather than direct system compromise. The attack vector is classified under remote code execution prerequisites in terms of initial access but functions primarily as an information disclosure mechanism via the network interface without requiring additional exploits like SQL injection or cross-site scripting.
Mitigation strategies must prioritize immediate version upgrades to address this authorization gap directly. Organizations running Checkmk 2.2.x should upgrade immediately, while those on older maintenance branches must apply patches corresponding to versions 2.3.0p50, 2.4.0p36, or preferably the latest stable release of 2.5.0 which includes p12 or higher. Until patching is feasible, administrators can implement compensating controls by restricting access to the background job API endpoints through network-level firewall rules if those interfaces are exposed externally, although this may impact legitimate administrative workflows. Additionally, enforcing strict role-based access control policies ensures that only high-privilege accounts interact with system maintenance functions where possible, reducing the attack surface available to lower-tier users who might attempt to enumerate these identifiers.