CVE-2026-40304: zrok is software for sharing web services, files, and network resources

Q: How do I fix CVE-2026-40304?

zrok: upgrade to 2.0.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-40304 being exploited?

CVE-2026-40304 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-40304 affect?

CVE-2026-40304 affects zrok. Severity is medium (CVSS 5.3). 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

Q: How urgent is CVE-2026-40304?

Priority 24/100. No elevated risk signals yet.

Routine

MEDIUM 5.3UPGRADE

CVE-2026-40304 is a medium-severity flaw (CVSS 5.3) affecting zrok. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-284, CWE-863
Published	2026-04-17
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: netfoundry

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-17 22:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

netfoundry zrok UPGRADE

Affected: < 2.0.1

Fixed in: 2.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy zrok || rpm -q zrok || zrok --version

2. UPGRADE to 2.0.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade zrok

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zrok

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40304?

zrok: upgrade to 2.0.1. Exact commands for each OS are on this page.

Is CVE-2026-40304 being exploited?

CVE-2026-40304 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40304 affect?

CVE-2026-40304 affects zrok. Severity is medium (CVSS 5.3). 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

How urgent is CVE-2026-40304?

Priority 24/100. No elevated risk signals yet.

Related CVEs

CVE-2026-40303 HIGH 7.5 UPGRADE zrok is software for sharing web services, files, and network resources
CVE-2026-40302 MEDIUM 6.1 UPGRADE zrok is software for sharing web services, files, and network resources
CVE-2026-42275 HIGH 8.7 UPGRADE zrok is software for sharing web services, files, and network resources
CVE-2026-45568 CRITICAL 9.1 UPGRADE zrok is software for sharing web services, files, and network resources
CVE-2026-45576 HIGH 7.5 UPGRADE zrok is software for sharing web services, files, and network resources

References

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