Handlebars provides the power necessary to let users build semantic templates. From 4.0.0 until 4.7.10, Handlebars.compile() and Handlebars.precompile() accept pre-parsed AST objects while validating only selected PathExpression, NumberLiteral, and BooleanLiteral values. This issue bypasses the AST validation introduced in version 4.7.9 for CVE-2026-33937. An attacker who can supply an object instead of a template string can place JavaScript expressions in unchecked values such as Program.blockParams.length, a non-PathExpression parameter depth, a non-string StringLiteral.value, or a non-string PathExpression.original. The compiler emits those values into generated JavaScript, causing code execution in the server process when compile output renders or wherever precompile output is loaded. Applications that pass only template strings are not affected. This issue is fixed in version 4.7.10.
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History
Tue, 06 Oct 2026 20:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Handlebars provides the power necessary to let users build semantic templates. From 4.0.0 until 4.7.10, Handlebars.compile() and Handlebars.precompile() accept pre-parsed AST objects while validating only selected PathExpression, NumberLiteral, and BooleanLiteral values. This issue bypasses the AST validation introduced in version 4.7.9 for CVE-2026-33937. An attacker who can supply an object instead of a template string can place JavaScript expressions in unchecked values such as Program.blockParams.length, a non-PathExpression parameter depth, a non-string StringLiteral.value, or a non-string PathExpression.original. The compiler emits those values into generated JavaScript, causing code execution in the server process when compile output renders or wherever precompile output is loaded. Applications that pass only template strings are not affected. This issue is fixed in version 4.7.10. | |
| Title | Handlebars: JavaScript Injection via AST Type Confusion in compile (Program.blockParams) | |
| Weaknesses | CWE-843 CWE-94 |
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cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-06T19:41:55.785Z
Reserved: 2026-10-06T16:49:40.590Z
Link: CVE-2026-106446
No data.
Status : Received
Published: 2026-10-06T20:17:26.430
Modified: 2026-10-06T20:17:26.430
Link: CVE-2026-106446
No data.
OpenCVE Enrichment
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