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ZrokApplication · Netfoundry

CVE-2026-40304

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-17
Fix available
A fix is available. Upgrade to 2.0.1 or later.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In zrok prior to 2.0.1, the unaccess handler contains a logical error in its ownership guard. When a frontend record has environment_id = NULL (indicating an admin-created global frontend), the ownership check condition short-circuits to false, allowing deletion without any ownership verification. A non-admin user who knows a global frontend token can call DELETE /api/v2/unaccess with their own environment ID to permanently delete the global frontend, disrupting all public shares routed through it.

MitigationUpgrade to zrok version 2.0.1 or later, which contains the patched ownership guard logic. As an interim measure, restrict knowledge of global frontend tokens to trusted administrators only.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ZrokApplication
Affected:< 2.0.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed zrok version
    Run 'zrok --version' or check the version of the zrok service/process running in your environment. Compare the version number to 2.0.1.
    Affected if The installed version is less than 2.0.1
  2. Check for global frontend records
    Query your zrok backend database or API to list frontend records. Look for any frontend entries where the environment_id field is NULL, indicating an admin-created global frontend.
    Affected if There exist frontend records with environment_id = NULL (global frontends) in your system
  3. Verify API endpoint access controls
    Examine the access control configuration for the DELETE /api/v2/unaccess endpoint. Determine whether non-admin users are permitted to invoke this endpoint.
    Affected if Non-administrator users have permission to call DELETE /api/v2/unaccess
  4. Audit for unauthorized unaccess deletions
    Review API access logs or audit trails for DELETE /api/v2/unaccess requests. Look for deletion events initiated by non-admin users that removed frontend records.
    Affected if Any DELETE /api/v2/unaccess requests were made by non-admin users, or global frontend records were deleted unexpectedly

You are affected if running zrok version less than 2.0.1 and your system contains global frontends (environment_id = NULL) that non-admin users can delete via the unaccess API endpoint.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.0.1 or later
Fixed in 2.0.1
Interim mitigation

Upgrade to zrok version 2.0.1 or later, which contains the patched ownership guard logic. As an interim measure, restrict knowledge of global frontend tokens to trusted administrators only.

Recommended fix High confidence

2.0.1

  1. Upgrade zrok to version 2.0.1 or later to apply the patched fix for the ownership guard logical error in the unaccess handler.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zrok Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-40304 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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