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Vulnerability record · CVE-2026-44966 · published 26 May 2026

CVE-2026-44966: Shepherdwind velocity.js prototype pollution vulnerability

SShepherdwind · Velocity.Js

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.

9.8 CVSS 3.1 Critical EPSS 0.61% · top 53.1% CWE-1321 · Prototype pollution
9.8CVSS 3.1 base score
0.61%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References, 1 tagged exploit
24 Jul 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/shepherdwind/velocity.js/security/advisories/GHSA-j658-c2gf-x6pq ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.6CVE-2026-34621Adobe Acrobat Reader prototype pollution leads to code executionAdobe Acrobat and Reader (versions 24.001.30356, 26.001.21367 and earlier) are affected by prototype pollution (CWE-1321) that can result in arbitrar…KEVEPSS 2.2%analysed

Source: NIST National Vulnerability Database (record CVE-2026-44966), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.