CVE-2026-44966: Shepherdwind Velocity.js

Critical severity, CVSS 9.8. EPSS: 0.6% chance of exploitation in the next 30 days.

Velocity.js is a JavaScript implementation of the Apache Velocity template engine. In 2.1.5 and earlier, a prototype pollution vulnerability was discovered in velocityjs. This issue occurs during the processing of #set directives in Velocity templates. If an application renders a template controlled by an attacker, it is possible to modify Object.prototype, potentially leading to Denial of Service (DoS) or Remote Code Execution (RCE) depending on the server environment.

Affected products

• Shepherdwind Velocity.js: up to and including 2.1.5

Published 2026-05-26. Last modified 2026-07-24.