Missing escape of HTML entities in Handlebars template compilation

• Rule ID: javascript_lang_handlebars_no_escape
• Languages: javascript
• Source: handlebars_no_escape.yml

Description

In Handlebars (a templating engine that dynamically generates HTML markup), setting noEscape to true disables escaping HTML entities within the template output itself. This poses a security vulnerability, particularly leading to Cross-Site Scripting (XSS) attacks if the template content comes from an untrusted source.

Remediations

• Do set noEscape to false while compiling Handlebars templates, to ensure that HTML entities are properly escaped, thus mitigating the risk of XSS vulnerabilities.

  Handlebars.compile(template, { noEscape: false });

References

• Handlebars compile docs
• OWASP XSS Prevention Cheat Sheet

Associated CWE

• CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

OWASP Top 10

• A03:2021 - Injection

Configuration

To skip this rule during a scan, use the following flag

bearer scan /path/to/your-project/ --skip-rule=javascript_lang_handlebars_no_escape

To run only this rule during a scan, use the following flag

bearer scan /path/to/your-project/ --only-rule=javascript_lang_handlebars_no_escape