CVE-2026-40302 Details
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.
A reflected cross-site scripting vulnerability has been identified in Zrok, a tool for sharing web services and network resources. This issue affects versions prior to 2.0.1. The vulnerability arises because the proxyUi template engine uses Go's text/template, which does not escape HTML, instead of html/template. In the GitHub OAuth callback handlers for both publicProxy and dynamicProxy, the attacker-controlled refreshInterval query parameter is embedded verbatim into an error message when time.ParseDuration fails. This error is then rendered unescaped into HTML. As a result, an attacker can send 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.
Users can upgrade to Zrok version 2.0.1 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 18, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/openziti/zrok/releases/tag/v2.0.1 | [email protected] | Release Notes |
| https://github.com/openziti/zrok/security/advisories/GHSA-4fxq-2x3x-6xqx | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-116 | Improper Encoding or Escaping of Output | [email protected] |
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| netfoundry zrok | < 2.0.1 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 23, 2026 | Initial Analysis | [email protected] |
| Apr 17, 2026 | New CVE Received | [email protected] |