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

CVE-2026-33940

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, a crafted object placed in the template context can bypass all conditional guards in `resolvePartial()` and cause `invokePartial()` to return `undefined`. The Handlebars runtime then treats the unresolved partial as a source that needs to be compiled, passing the crafted object to `env.compile()`. Because the object is a valid Handlebars AST containing injected code, the generated JavaScript executes arbitrary commands on the server. The attack requires the adversary to control a value that can be returned by a dynamic partial lookup. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build (`require('handlebars/runtime')`). Without `compile()`, the fallback compilation path in `invokePartial` is unreachable. Second, sanitize context data before rendering: Ensure no value in the context is a non-primitive object that could be passed to a dynamic partial. Third, avoid dynamic partial lookups (`{{> (lookup ...)}}`) when context data is user-controlled.

Productos y versiones vulnerables

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