CVE-2026-44966
Analyzed Analyzed - Analysis Complete
Prototype Pollution in Velocity.js Template Engine

Publication date: 2026-05-26

Last updated on: 2026-06-02

Assigner: GitHub, Inc.

Description
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.
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Meta Information
Published
2026-05-26
Last Modified
2026-06-02
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-14
NVD
CVE-2026-44966
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
shepherdwind velocity.js to 2.1.5 (inc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-1321 The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
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Executive Summary

Velocity.js is a JavaScript implementation of the Apache Velocity template engine. In versions 2.1.5 and earlier, there is a prototype pollution vulnerability that occurs during the processing of #set directives in Velocity templates. If an attacker controls the template being rendered by an application, they can modify the Object.prototype, which is a fundamental JavaScript object. This manipulation can lead to serious security issues.

Impact Analysis

Exploiting this vulnerability can allow an attacker to cause Denial of Service (DoS) or even Remote Code Execution (RCE) depending on the server environment where the application is running. This means an attacker could disrupt the availability of the service or execute arbitrary code remotely, potentially compromising the entire system.

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