Severity
4.7MEDIUMNVD
GHSA9.8OSV9.8
EPSS
0.0%
top 87.27%
CISA KEV
Not in KEV
Exploit
No known exploits
Timeline
PublishedMar 27
Latest updateMar 28

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 reflec

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:NExploitability: 1.6 | Impact: 2.7

Affected Packages3 packages

NVDhandlebarsjs/handlebars4.0.04.7.9
npmhandlebarsjs/handlebars4.0.04.7.9
CVEListV5handlebars-lang/handlebars.js>= 4.0.0, < 4.7.9

Patches

🔴Vulnerability Details

4
CVEList
Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection2026-03-27
OSV
CVE-2026-33916: Handlebars provides the power necessary to let users build semantic templates2026-03-27
OSV
Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection2026-03-26
GHSA
Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection2026-03-26

📋Vendor Advisories

2
Red Hat
handlebars.js: Handlebars: Cross-Site Scripting (XSS) via prototype pollution in partial resolution2026-03-27
Debian
CVE-2026-33916: node-handlebars - Handlebars provides the power necessary to let users build semantic templates. I...2026

🕵️Threat Intelligence

1
Wiz
CVE-2026-33916 Impact, Exploitability, and Mitigation Steps | Wiz

💬Community

3
Bugzilla
CVE-2026-33916 openbao: Handlebars: Cross-Site Scripting (XSS) via prototype pollution in partial resolution [fedora-all]2026-03-28
Bugzilla
CVE-2026-33916 nextcloud: Handlebars: Cross-Site Scripting (XSS) via prototype pollution in partial resolution [epel-all]2026-03-28
Bugzilla
CVE-2026-33916 openbao: Handlebars: Cross-Site Scripting (XSS) via prototype pollution in partial resolution [epel-all]2026-03-28
CVE-2026-33916 — Cross-site Scripting in Handlebars | cvebase