CVE-2026-40302: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in openziti zrok
CVE-2026-40302 is a cross-site scripting (XSS) vulnerability in openziti zrok versions prior to 2. 0. 1. The issue arises because the proxyUi template engine uses Go's text/template, which does not perform HTML escaping, instead of html/template. Specifically, the GitHub OAuth callback handlers embed the attacker-controlled refreshInterval query parameter directly into an error message that is rendered unescaped in HTML. This allows an attacker to craft a login URL that, after the victim completes the OAuth flow, causes arbitrary JavaScript execution in the OAuth server's origin. Version 2. 0. 1 addresses this vulnerability.
AI Analysis
Technical Summary
The vulnerability in openziti zrok (before version 2.0.1) is due to improper neutralization of input during web page generation (CWE-79). The proxyUi template engine uses Go's text/template which lacks HTML escaping, causing the attacker-controlled refreshInterval query parameter to be embedded verbatim into an error message when time.ParseDuration fails. This error message is then rendered unescaped into HTML in the GitHub OAuth callback handlers (publicProxy and dynamicProxy). An attacker can exploit this by delivering a crafted login URL that triggers arbitrary JavaScript execution in the OAuth server's origin after the victim completes the OAuth flow. The vulnerability has a CVSS 3.1 score of 6.1 (medium severity). The issue is fixed in version 2.0.1.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the OAuth server's origin after a victim completes the GitHub OAuth flow. This can lead to information disclosure or session manipulation limited to the OAuth server's origin. The vulnerability does not impact availability and requires user interaction (UI:R). The CVSS score is 6.1, indicating a medium severity impact with confidentiality and integrity impacts.
Mitigation Recommendations
Upgrade openziti zrok to version 2.0.1 or later, where the vulnerability is patched by switching to the html/template engine that performs proper HTML escaping. No other mitigation is indicated or required as the fix is available in the official release.
CVE-2026-40302: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in openziti zrok
Description
CVE-2026-40302 is a cross-site scripting (XSS) vulnerability in openziti zrok versions prior to 2. 0. 1. The issue arises because the proxyUi template engine uses Go's text/template, which does not perform HTML escaping, instead of html/template. Specifically, the GitHub OAuth callback handlers embed the attacker-controlled refreshInterval query parameter directly into an error message that is rendered unescaped in HTML. This allows an attacker to craft a login URL that, after the victim completes the OAuth flow, causes arbitrary JavaScript execution in the OAuth server's origin. Version 2. 0. 1 addresses this vulnerability.
CVSS v3.1
Score 6.1medium
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in openziti zrok (before version 2.0.1) is due to improper neutralization of input during web page generation (CWE-79). The proxyUi template engine uses Go's text/template which lacks HTML escaping, causing the attacker-controlled refreshInterval query parameter to be embedded verbatim into an error message when time.ParseDuration fails. This error message is then rendered unescaped into HTML in the GitHub OAuth callback handlers (publicProxy and dynamicProxy). An attacker can exploit this by delivering a crafted login URL that triggers arbitrary JavaScript execution in the OAuth server's origin after the victim completes the OAuth flow. The vulnerability has a CVSS 3.1 score of 6.1 (medium severity). The issue is fixed in version 2.0.1.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the OAuth server's origin after a victim completes the GitHub OAuth flow. This can lead to information disclosure or session manipulation limited to the OAuth server's origin. The vulnerability does not impact availability and requires user interaction (UI:R). The CVSS score is 6.1, indicating a medium severity impact with confidentiality and integrity impacts.
Mitigation Recommendations
Upgrade openziti zrok to version 2.0.1 or later, where the vulnerability is patched by switching to the html/template engine that performs proper HTML escaping. No other mitigation is indicated or required as the fix is available in the official release.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-10T20:22:44.036Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e2a136bdfbbecc59908367
Added to database: 4/17/2026, 9:08:06 PM
Last enriched: 4/25/2026, 3:03:14 AM
Last updated: 6/4/2026, 8:38:18 AM
Views: 75
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