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CVE-2026-33916

4.7 · MEDIUM
Published Mar 27, 2026 handlebarsjs CWE-79

Overview

CVE-2026-33916 is a medium-severity vulnerability affecting handlebarsjs handlebars. It was published on March 27, 2026 and has a CVSS 3.1 base score of 4.7 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 4.7, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical Description

Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `resolvePartial()` in the Handlebars runtime resolves partial names via a plain property lookup on `options.partials` without guarding against prototype-chain traversal. When `Object.prototype` has been polluted with a string value whose key matches a partial reference in a template, the polluted string is used as the partial body and rendered without HTML escaping, resulting in reflected or stored XSS. Version 4.7.9 fixes the issue. Some workarounds are available. Apply `Object.freeze(Object.prototype)` early in application startup to prevent prototype pollution. Note: this may break other libraries, and/or use the Handlebars runtime-only build (`handlebars/runtime`), which does not compile templates and reduces the attack surface.

Remediation

Check the references section for vendor advisories and patches from handlebarsjs. Update handlebars to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status
handlebarsjs handlebars >= 4.0.0, < 4.7.9 Affected

Frequently Asked Questions

What is CVE-2026-33916?

CVE-2026-33916 is a medium-severity vulnerability affecting handlebarsjs handlebars. It was published on March 27, 2026 and has a CVSS 3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2026-33916?

This vulnerability has a CVSS 3.1 base score of 4.7, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-33916?

Check the references section for vendor advisories and patches from handlebarsjs. Update handlebars to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-33916?

CyberStrike's AI-powered security agents can automatically detect CVE-2026-33916 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.

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