cvedb.io
CVE-2026-33937
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2026-03-27T21:17:27.417 · Last modified 2026-07-02T12:17:08.447

Summary

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

Affected products

handlebarsjs — handlebars

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.