---
id: CVE-2026-106446
title: Handlebars provides the power necessary to let users build semantic templates
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,
  NumberL…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-94
  - CWE-843
vendor: handlebars-lang
product: handlebars.js
affected:
  - 'handlebars.js >= 4.0.0, < 4.7.10'
published: '2026-10-06'
updated: '2026-10-07'
sourceUpdated: '2026-10-07T19:17:32.293'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-106446'
references:
  - url: >-
      https://github.com/handlebars-lang/handlebars.js/commit/703fdcc5fd6cc8d1cc0c33cc19de40c467c4b8d2
    label: security-advisories@github.com
  - url: 'https://github.com/handlebars-lang/handlebars.js/pull/2185'
    label: security-advisories@github.com
  - url: 'https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.10'
    label: security-advisories@github.com
  - url: >-
      https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-8r5x-fm3f-whwj
    label: security-advisories@github.com
  - url: >-
      https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-8r5x-fm3f-whwj
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-106446'
  - url: 'https://github.com/advisories/GHSA-8r5x-fm3f-whwj'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-106446.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-106446'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2547120'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-106446'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - npm
  - csaf
  - vex
  - red-hat
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-07T18:27:28.577129Z'
ingestedAt: '2026-10-06T20:16:42.484Z'
epss: 0.00786
epssPercentile: 0.5593
aliases:
  - GHSA-8r5x-fm3f-whwj
ecosystem: npm
patched:
  - handlebars 4.7.10
scores:
  nvd: 9.8
  vendor: 8.1
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-106446)

Affected packages:

- `handlebars >= 4.0.0, <= 4.7.9`

Patched in:

- `handlebars 4.7.10`

Source: https://github.com/advisories/GHSA-8r5x-fm3f-whwj

## Vendor advisories

- **Red Hat VEX** · Important · affected: Cryostat 4, Multicluster Engine for Kubernetes, Node HealthCheck Operator, Red Hat Advanced Cluster Management for Kubernetes 2, Red Hat AMQ Broker 7, Red Hat build of Apache Camel - HawtIO 4, … · no fix planned: Cryostat 4, Multicluster Engine for Kubernetes, Node HealthCheck Operator, Red Hat Advanced Cluster Management for Kubernetes 2, … · updated 2026-10-13 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-106446.json)