Platform
other
Component
checkmate
Fixed in
3.5.2
CVE-2026-31836 describes a privilege escalation vulnerability discovered in Checkmate, an open-source server monitoring tool. This flaw allows authenticated users to bypass role-based access controls and gain superadmin privileges, granting them complete control over the application. The vulnerability impacts versions 3.5.1 and earlier, and a fix is currently available.
The impact of this vulnerability is significant. An attacker exploiting CVE-2026-31836 can elevate their privileges to superadmin within Checkmate. This grants them unrestricted access to all application features and data, including user management, configuration settings, and potentially sensitive system information. They could modify critical configurations, delete data, or even compromise the underlying server if Checkmate is configured with excessive permissions. The ability to view all users and their associated data represents a serious privacy risk. This vulnerability highlights the importance of robust access control mechanisms in self-hosted applications.
CVE-2026-31836 was publicly disclosed on 2026-03-20. The vulnerability's ease of exploitation, combined with Checkmate's popularity as a self-hosted monitoring solution, suggests a potential for widespread exploitation. There are currently no known public proof-of-concept exploits, but the vulnerability's nature makes it likely that one will emerge. It has not yet been added to the CISA KEV catalog. The CVSS score of 8.1 (HIGH) reflects the potential for significant impact.
Exploit Status
EPSS
0.03% (9% percentile)
CISA SSVC
CVSS Vector
The primary mitigation for CVE-2026-31836 is to upgrade Checkmate to a patched version. The vendor has not specified a fixed version, so consult their official advisory for the latest release. If upgrading is not immediately feasible, consider implementing stricter authentication and authorization policies within Checkmate. Review user roles and permissions to ensure the principle of least privilege is enforced. While a WAF or proxy cannot directly prevent this mass assignment vulnerability, they can be configured to monitor for suspicious user profile modification requests. Monitor Checkmate logs for unusual user activity or attempts to modify user roles.
Update to a patched version once it is available. Currently, there are no publicly available patches, so it is recommended to monitor the Checkmate repository for updates and apply the patch as soon as it is published.
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CVE-2026-31836 is a vulnerability in Checkmate versions ≤3.5.1 that allows authenticated users to escalate their privileges to superadmin, bypassing access controls.
You are affected if you are using Checkmate version 3.5.1 or earlier. Check your version and upgrade as soon as possible.
Upgrade Checkmate to a patched version. Consult the official Checkmate advisory for the latest release and instructions.
There are currently no confirmed reports of active exploitation, but the vulnerability's nature suggests a potential for exploitation.
Refer to the official Checkmate project website and security advisories for the latest information and updates.
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