CVE-2026-33916 in Handlebars
Résumé (Anglaise)
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.
Divulgation
27/03/2026
Entrées
VulDB provides additional information and datapoints for this CVE:
| ID | Vulnérabilité | CWE | Exp | Con | CVE |
|---|---|---|---|---|---|
| 353828 | Handlebars cross site scripting | 79 | Non défini | Correctif officiel | CVE-2026-33916 |