Resource exhaustion in Netfoundry 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 validation occurs. The function is reached on every request to an OAuth-protected proxy share, allowing an unauthenticated remote attacker to trigger gigabyte-scale heap allocations per request, leading to process-level OOM termination or repeated goroutine panics. Both publicProxy and dynamicProxy are affected. Version 2.0.1 patches the issue.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.006 (46.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001
Affected products
- Netfoundry Zrok
- Openziti Zrok — versions < 2.0.1
Weakness classification (CWE)
References
- github.com/openziti/zrok/security/advisories/GHSA-cpf9-ph2j-ccr9 (Vendor Advisory)
- github.com/openziti/zrok/releases/tag/v2.0.1 (Release Notes)
Frequently asked questions
- What is CVE-2026-40303?
- CVE-2026-40303 is a high-severity vulnerability in Netfoundry 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.