CVE-2026-40302 MEDIUM

CVE-2026-40302: zrok has reflected XSS in GitHub OAuth callback via unsanitized refreshInterval error rendering

Vendor Openziti
Product zrok
Weakness CWE-79 · XSS
Published April 17, 2026
Last update April 18, 2026

CVSS base score

6.1/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 17, 2026 CVE published
April 18, 2026 Record updated

Related vulnerabilities

04Related CVE