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CVE-2026-33938 (High) detected in handlebars-4.0.11.tgz #159

Description

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CVE-2026-33938 - High Severity Vulnerability

Vulnerable Library - handlebars-4.0.11.tgz

Handlebars provides the power necessary to let you build semantic templates effectively with no frustration

Library home page: https://registry.npmjs.org/handlebars/-/handlebars-4.0.11.tgz

Path to dependency file: /package.json

Path to vulnerable library: /node_modules/handlebars/package.json

Dependency Hierarchy:

  • lerna-3.2.1.tgz (Root Library)
    • version-3.2.0.tgz
      • conventional-commits-3.0.2.tgz
        • conventional-changelog-core-2.0.11.tgz
          • conventional-changelog-writer-3.0.9.tgz
            • handlebars-4.0.11.tgz (Vulnerable Library)

Found in HEAD commit: 540c99a1154755210d6564a50420589ebbf7f97c

Found in base branch: master

Vulnerability Details

Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the "@partial-block" special variable is stored in the template data context and is reachable and mutable from within a template via helpers that accept arbitrary objects. When a helper overwrites "@partial-block" with a crafted Handlebars AST, a subsequent invocation of "{{> @partial-block}}" compiles and executes that AST, enabling arbitrary JavaScript execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build ("require('handlebars/runtime')"). The "compile()" method is absent, eliminating the vulnerable fallback path. Second, audit registered helpers for any that write arbitrary values to context objects. Helpers should treat context data as read-only. Third, avoid registering helpers from third-party packages (such as "handlebars-helpers") in contexts where templates or context data can be influenced by untrusted input.

Publish Date: 2026-03-27

URL: CVE-2026-33938

CVSS 3 Score Details (8.1)

Base Score Metrics:

  • Exploitability Metrics:
    • Attack Vector: Network
    • Attack Complexity: High
    • Privileges Required: None
    • User Interaction: None
    • Scope: Unchanged
  • Impact Metrics:
    • Confidentiality Impact: High
    • Integrity Impact: High
    • Availability Impact: High

For more information on CVSS3 Scores, click here.

Suggested Fix

Type: Upgrade version

Release Date: 2026-03-27

Fix Resolution: https://github.com/handlebars-lang/handlebars.js.git - v4.7.9

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