Checkmate: Improper Privilege Management
CVE-2026-31836 is a high-severity improper privilege management vulnerability in Checkmate from Bluewave-labs, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Checkmate versions: <= 3.5.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Checkmate you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Bluewave-labs | Checkmate | <= 3.5.1 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (github.com).
Official description
Checkmate is an open-source, self-hosted tool designed to track and monitor server hardware, uptime, response times, and incidents in real-time with beautiful visualizations. In versions from 3.5.1 and prior, a mass assignment vulnerability in Checkmate's user profile update endpoint allows any authenticated user to escalate their privileges to superadmin, bypassing all role-based access controls. An attacker can modify their user role to gain complete administrative access to the application, including the ability to view all users, modify critical configurations, and access sensitive system data. At time of publication, there are no publicly available patches.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Privilege Management
The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
How developers prevent this class of flaw
- Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource.
More Improper Privilege Management vulnerabilities (CWE-269)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Checkmate
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Privilege Management vulnerabilities
- 9.8 Critical severity
- 7.2 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
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