CVE-2026-40304: zrok's broken ownership check in DELETE /api/v2/unaccess allows non-admin to delete global frontend records

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-17 · updated 2026-10-26
Weakness: CWE-284

Description

zrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, the unaccess handler (controller/unaccess.go) contains a logical error in its ownership guard: when a frontend record has environment_id = NULL (the marker for admin-created global frontends), the condition short-circuits to false and allows the deletion to proceed without any ownership verification. A non-admin user who knows a global frontend token can call DELETE /api/v2/unaccess with any of their own environment IDs and permanently delete the global frontend, taking down all public shares routed through it. Version 2.0.1 patches the issue.

Affected products

openziti zrok: before 2.0.1 — fixed in 2.0.1

How to fix

Upgrade to a fixed version: openziti zrok 2.0.1. Check the vendor advisory for mitigations.

References

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