Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, when a Handlebars template contains decorator syntax referencing an unregistered decorator (e.g. `{{*n}}`), the compiled template calls `lookupProperty(decorators, "n")`, which returns `undefined`. The runtime then immediately invokes the result as a function, causing an unhandled `TypeError: ... is not a function` that crashes the Node.js process. Any application that compiles user-supplied templates without wrapping the call in a `try/catch` is vulnerable to a single-request Denial of Service. Version 4.7.9 fixes the issue. Some workarounds are available. Wrap compilation and rendering in `try/catch`. Validate template input before passing it to `compile()`; reject templates containing decorator syntax (`{{*...}}`) if decorators are not used in your application. Use the pre-compilation workflow; compile templates at build time and serve only pre-compiled templates; do not call `compile()` at request time.
References
Configurations
No configuration.
History
30 Mar 2026, 19:16
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-9cx6-37pm-9jff - |
Information
Published : 2026-03-27 22:16
Updated : 2026-03-30 19:16
NVD link : CVE-2026-33939
Mitre link : CVE-2026-33939
CVE.ORG link : CVE-2026-33939
JSON object : View
Products Affected
No product.
CWE
CWE-754
Improper Check for Unusual or Exceptional Conditions