What is CVE-2026-40303?

CVE-2026-40303 is a high-severity vulnerability in Openziti Zrok, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-04-17.

How severe is CVE-2026-40303?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Openziti Zrok

CVE-2026-40303

zrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, endpoints.GetSessionCookie parses an attacker-supplied cookie chunk count and calls make([]string, count) with no upper bound before any token…

Vulnerability class: DoS (Denial of Service)

EPSS: 0.000 (9.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Openziti Zrok — versions < 2.0.1

Weakness classification (CWE)

References

https://github.com/openziti/zrok/security/advisories/GHSA-cpf9-ph2j-ccr9 (x_refsource_CONFIRM)
https://github.com/openziti/zrok/releases/tag/v2.0.1 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-40303?: CVE-2026-40303 is a high-severity vulnerability in Openziti Zrok, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-04-17.
How severe is CVE-2026-40303?: High severity. CVSS v3 base score is 7.5 out of 10.