CVE-2026-33916 describes a medium-severity prototype pollution vulnerability in Handlebars.js versions 4.0.0 through 4.7.8. This flaw allows an attacker to inject arbitrary string values into Object.prototype, which can then be rendered without HTML escaping, leading to reflected or stored Cross-Site Scripting (XSS). With a CVSS score of 4.7, exploitation requires a network attack vector, high attack complexity, and user interaction. There is currently no evidence of active exploitation, public exploit code, or significant community discussion regarding this vulnerability.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
>= 4.0.0, < 4.7.9CPE matchmatch criteria | cpe:2.3:a:handlebarsjs:handlebars:*:*:*:*:*:node.js:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
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