Description

Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `resolvePartial()` in the Handlebars runtime resolves partial names via a plain property lookup on `options.partials` without guarding against prototype-chain traversal. When `Object.prototype` has been polluted with a string value whose key matches a partial reference in a template, the polluted string is used as the partial body and rendered without HTML escaping, resulting in reflected or stored XSS. Version 4.7.9 fixes the issue. Some workarounds are available. Apply `Object.freeze(Object.prototype)` early in application startup to prevent prototype pollution. Note: this may break other libraries, and/or use the Handlebars runtime-only build (`handlebars/runtime`), which does not compile templates and reduces the attack surface.

INFO

Published Date :

2026-03-27T21:00:48.624Z

Last Modified :

2026-03-30T15:41:36.977Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-33916 vulnerability.

Vendors Products
Handlebarsjs
  • Handlebars

CVSS Vulnerability Scoring System

Detailed values of each vector for above chart.
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