CVE-2026-33937
Handlebars.js has JavaScript Injection via AST Type Confusion
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.
INFO
Published Date :
March 27, 2026, 9:17 p.m.
Last Modified :
March 31, 2026, 5:49 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update Handlebars to version 4.7.9 or later.
- Validate input type before calling Handlebars.compile().
- Use handlebars/runtime on server if templates are pre-compiled.
Public PoC/Exploit Available at Github
CVE-2026-33937 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-33937.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33937 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-33937
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
CVE-2026-33937 Handlebars RCE exploit PoC (AST Injection)
exploit handlebars nodejs poc rce security ssti template-injection vulnerability ast-injection cve-2026-33937
Dockerfile Shell JavaScript
None
CVE POC repo 자동 수집기
Python
📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.
security cve exploit poc vulnerability
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33937 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33937 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 31, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:* versions from (including) 4.0.0 up to (excluding) 4.7.9 Added Reference Type GitHub, Inc.: https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q Types: Exploit, Vendor Advisory -
New CVE Received by [email protected]
Mar. 27, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-94 Added CWE CWE-843 Added Reference https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2 Added Reference https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9 Added Reference https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q