CVE-2026-40304
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
zrok prior to version 2.0.1 contains a logical error in the ownership guard in the unaccess handler (controller/unaccess.go): when a frontend record has environment_id = NULL (the marker for admin-created global frontends), the condition short-circuits to false and allows deletion without ownership verification. A non-admin user who knows a global frontend token can permanently delete the global frontend, causing all public shares routed through it to become unavailable.
Risk Assessment
Unauthorized deletion of a global frontend leads to service unavailability for all users relying on that frontend.
Recommendation
Update zrok to version 2.0.1, which fixes this vulnerability.
Other vulnerabilities in zrok
See all- CVE-2026-45568Critical
A vulnerability in zrok before version 2.0.3 allows an attacker to pass an absolute URL in the request path to the Flask proxy route of the Python SDK. The urllib.parse.urljoin function enables replacing the configured target host, causing the server to make a request to an attacker-chosen URL.
- CVE-2026-45576High
A vulnerability in zrok (versions 0.4.23 through 2.0.3) allows an attacker to write files outside the selected local destination root via attacker-controlled WebDAV or zrok drive paths like /../outside.txt. The issue is fixed in version 2.0.3.
- CVE-2026-40302Medium
zrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, the proxyUi template engine uses Go's text/template (no HTML escaping) instead of html/template, and the GitHub OAuth callback handlers in publicProxy and dynamicProxy embed the attacker-controlled refreshInterval parameter unescaped into an error message. An attacker can deliver a crafted login URL so that, after the victim completes the GitHub OAuth flow, the callback page executes arbitrary JavaScript in the OAuth server's origin.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS