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.
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| handlebars-lang | handlebars.js | affected |
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Remediation
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Tracking
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Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-2w6w-674q-4c4q | Handlebars.js has JavaScript Injection via AST Type Confusion |
References
History
Sat, 28 Mar 2026 03:15:00 +0000
| Type | Values Removed | Values 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. | |
| Title | Handlebars.js has JavaScript Injection via AST Type Confusion | |
| Weaknesses | CWE-843 CWE-94 |
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| Metrics |
cvssV3_1
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-03-27T21:03:46.748Z
Reserved: 2026-03-24T19:50:52.103Z
Link: CVE-2026-33937
Vulnrichment
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NVD
Status : Received
Published: 2026-03-27T21:17:27.417
Modified: 2026-03-27T21:17:27.417
Link: CVE-2026-33937
Redhat
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OpenCVE Enrichment
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