Paper/Archive/CVE-2026-73649

CVE-2026-73649

shepherdwind velocity.js — Velocity.js: Remote Code Execution via property-read to Function constructor (bypass of CVE-2026-44966 fix)

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
velocity.js< 2.1.7–CNA

Scores by source

GitHub_M (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitgithub.com/shepherdwind/velocity.js/security/advisories/GHSA-7gfh-x38p-prh3refgithub.com/shepherdwind/velocity.js/pull/192refgithub.com/shepherdwind/velocity.js/commit/f8e47a6c4607249b9c967d3a1ced959b4dd64dbarefgithub.com/shepherdwind/velocity.js/releases/tag/v2.1.7