Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

CVE-2026-33938

Gravedad CVSS v3.1:
ALTA
Tipo:
CWE-94 Control incorrecto de generación de código (Inyección de código)
Fecha de publicación:
27/03/2026
Última modificación:
31/03/2026

Descripción

*** Pendiente de traducción *** Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the `@partial-block` special variable is stored in the template data context and is reachable and mutable from within a template via helpers that accept arbitrary objects. When a helper overwrites `@partial-block` with a crafted Handlebars AST, a subsequent invocation of `{{> @partial-block}}` compiles and executes that AST, enabling arbitrary JavaScript execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build (`require('handlebars/runtime')`). The `compile()` method is absent, eliminating the vulnerable fallback path. Second, audit registered helpers for any that write arbitrary values to context objects. Helpers should treat context data as read-only. Third, avoid registering helpers from third-party packages (such as `handlebars-helpers`) in contexts where templates or context data can be influenced by untrusted input.

Productos y versiones vulnerables

CPE Desde Hasta
cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:* 4.0.0 (incluyendo) 4.7.9 (excluyendo)