How severe is CVE-2026-40304?

CVE-2026-40304 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-40304 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40304?

CVE-2026-40304 affects Netfoundry Zrok. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40304?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40304 have an EU (EUVD) identifier?

Yes. CVE-2026-40304 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23551.

When was CVE-2026-40304 published?

CVE-2026-40304 was published on 2026-04-17 and last updated on 2026-06-17.

CVE-2026-40304

CVE-2026-40304 is a medium-severity vulnerability in Netfoundry Zrok with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23551
Weakness: CWE-284
Affected product: Netfoundry Zrok
Published: 2026-04-17
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-40304?: 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.
How severe is CVE-2026-40304?: CVE-2026-40304 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-40304 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40304?: CVE-2026-40304 affects Netfoundry Zrok. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40304?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40304 have an EU (EUVD) identifier?: Yes. CVE-2026-40304 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23551.
When was CVE-2026-40304 published?: CVE-2026-40304 was published on 2026-04-17 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:netfoundry:zrok:*:*:*:*:*:*:*:*

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