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HIGH

CVE-2026-85390

CVSS v3

7.1

HIGH

EPSS Score

0.5 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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.

Technical details

Published
2026-09-03
Last Modified
2026-09-05

Frequently asked questions

What is CVE-2026-85390?

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.

Is CVE-2026-85390 actively exploited?

Active exploitation of CVE-2026-85390 has not been confirmed. Its EPSS score was 0.5% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-85390?

CVE-2026-85390 has a CVSS v3 base score of 7.1 (HIGH severity).

Is CVE-2026-85390 affecting your environment?

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