shepherdwind Velocity.js up to 2.1.6 Property-Read Expressions references.ts getReferences os command injection

Summaryinfo

A vulnerability has been found in shepherdwind Velocity.js up to 2.1.6 and classified as critical. Impacted is the function getReferences of the file src/compile/references.ts of the component Property-Read Expressions. The manipulation leads to os command injection. This vulnerability is referenced as CVE-2026-73649. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in shepherdwind Velocity.js up to 2.1.6. It has been rated as critical. This issue affects the function getReferences of the file src/compile/references.ts of the component Property-Read Expressions. The manipulation with an unknown input leads to a os command injection vulnerability. Using CWE to declare the problem leads to CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Velocity.js is a JavaScript implementation of the Apache Velocity template engine. Prior to 2.1.7, the earlier fix for CVE-2026-44966 filtered constructor, __proto__, and prototype only in the #set assignment handler in src/compile/set.ts, while property-read expressions in src/compile/references.ts remained unfiltered. The getReferences() flow called getAttributes(), whose property access allowed an attacker-controlled template to traverse constructor.constructor to the JavaScript Function constructor. The #set handler validated only the assignment target and did not inspect the right-hand property-read expression, allowing arbitrary shell commands, environment-variable access, cloud-credential access, and internal-network access in the server process. This issue is fixed in version 2.1.7.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-73649 since 08/13/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

Upgrading to version 2.1.7 eliminates this vulnerability.

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Productinfo

Type

• JavaScript Library

Vendor

• shepherdwind

Name

• Velocity.js

Version

• 2.1.0
• 2.1.1
• 2.1.2
• 2.1.3
• 2.1.4
• 2.1.5
• 2.1.6

Website

• Product: https://github.com/shepherdwind/velocity.js/

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