Handlebars.js has JavaScript Injection via AST Type Confusion
En bref
Sévérité
CRITICAL 9.8
EPSS
EPSS 1.91 % · centile 80 (2026-10-27)
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
GitHub_M
Statut NVD
Modified
Description
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.
