CVE-2026-73649

Critical

Description

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.

SeverityCritical
CVSS9.8
Exploit probability—
ProductVelocityjs
PublishedAug 13, 2026
First seenAug 13, 2026

How to fix

Update
  • velocityjs2.1.7 or later

Affected products

ProductAffected versionsFixed in
velocityjsnpmv < 2.1.72.1.7

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CVE-2026-73649 · Velocityjs · Dark Radar