CVE-2026-106446 (GCVE-0-2026-106446)

Vulnerability from cvelistv5 – Published: 2026-10-06 19:41 – Updated: 2026-10-07 18:30
VLAI
Title
Handlebars: JavaScript Injection via AST Type Confusion in compile (Program.blockParams)
Summary
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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-07 18:27 UTC
CWE
  • CWE-94 - Improper Control of Generation of Code ('Code Injection')
  • CWE-843 - Access of Resource Using Incompatible Type ('Type Confusion')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7634 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
handlebars-lang handlebars.js Affected: >= 4.0.0, < 4.7.10
guessed Create a notification for this product.
Show details on NVD website
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