Description
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.
INFO
Published Date :
2026-03-27T21:08:24.664Z
Last Modified :
2026-03-30T18:52:24.142Z
Source :
GitHub_M
AFFECTED PRODUCTS
The following products are affected by CVE-2026-33939 vulnerability.
| Vendors | Products |
|---|---|
| Handlebarsjs |
|
REFERENCES
Here, you will find a curated list of external links that provide in-depth information to CVE-2026-33939.
