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Vulnerability record · CVE-2026-40302 · published 17 April 2026

CVE-2026-40302: Netfoundry zrok cross-site scripting vulnerability

Netfoundry · Zrok

zrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, the proxyUi template engine uses Go's text/template (which performs no HTML escaping) instead of html/template. The GitHub OAuth callback handlers in both publicProxy and dynamicProxy embed the attacker-controlled refreshInterval query parameter verbatim into an error message when time.ParseDuration fails, and render that error unescaped into HTML. An attacker can deliver a crafted login URL to a victim; after the victim completes the GitHub OAuth flow, the callback page executes arbitrary JavaScript in the OAuth server's origin. Version 2.0.1 patches the issue.

6.1 CVSS 3.1 Medium EPSS 0.26% · top 83.8% CWE-79 · Cross-site scriptingCWE-116 · CWE-116
6.1CVSS 3.1 base score
0.26%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

zrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, the proxyUi template engine uses Go's text/template (which performs no HTML escaping) instead of html/template. The GitHub OAuth callback handlers in both publicProxy and dynamicProxy embed the attacker-controlled refreshInterval query parameter verbatim into an error message when time.ParseDuration fails, and render that error unescaped into HTML. An attacker can deliver a crafted login URL to a victim; after the victim completes the GitHub OAuth flow, the callback page executes arbitrary JavaScript in the OAuth server's origin. Version 2.0.1 patches the issue.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/openziti/zrok/releases/tag/v2.0.1 Release Notes
https://github.com/openziti/zrok/security/advisories/GHSA-4fxq-2x3x-6xqx Vendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-40302), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.