CVE-2026-33937
CRITICALHandlebars.js has JavaScript Injection via AST Type Confusion
Title source: cnaExploitation Summary
EIP tracks 2 public exploits for CVE-2026-33937. PoCs published by EQSTLab, dinhvaren.
AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-33937, leveraging Handlebars AST injection to achieve remote code execution (RCE) via crafted template data. The exploit includes a Dockerized vulnerable environment and an interactive Python script to execute arbitrary commands.
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.
Exploits (2)
This repository contains a functional exploit for CVE-2026-33937, leveraging Handlebars AST injection to achieve remote code execution (RCE) via crafted template data. The exploit includes a Dockerized vulnerable environment and an interactive Python script to execute arbitrary commands.
This repository contains a functional exploit for CVE-2026-33937, demonstrating an RCE vulnerability in Handlebars.js via AST type confusion. The PoC leverages a crafted AST object to inject arbitrary JavaScript code during template compilation.
References (3)
Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H