Vulnerability 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.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/shepherdwind/velocity.js/commit/f8e47a6c4607249b9c967d3a1ced9
- https://github.com/shepherdwind/velocity.js/pull/192
- https://github.com/shepherdwind/velocity.js/releases/tag/v2.1.7
- https://github.com/shepherdwind/velocity.js/security/advisories/GHSA-7gfh-x38p-p
- https://github.com/shepherdwind/velocity.js/security/advisories/GHSA-7gfh-x38p-p
FAQ
What is CVE-2026-73649?
CVE-2026-73649 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 as...
How severe is CVE-2026-73649?
CVE-2026-73649 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-73649?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.