CVE-2026-73602

Flowise before 3.1.3 contains a sandbox escape (code injection, CWE-95) in the vm2 JavaScript sandbox used to run user-supplied code, exploitable through a validation bypass in the moment locale check. An authenticated user can supply a crafted fake String object whose 'match' function defeats path traversal checks, causing Flowise to load and execute attacker-controlled JavaScript files from the document store outside the sandbox. Successful exploitation yields arbitrary code execution on the host running Flowise, with high impact to confidentiality, integrity, and availability (CVSS v4.0 score 9, network vector with low privileges required and no user interaction). Any Flowise deployment older than 3.1.3 that permits authenticated users to execute custom JavaScript is affected, with internet-exposed instances facing the greatest risk. The flaw is not yet in CISA KEV and EPSS estimates a 0.8% probability of exploitation within 30 days (56th percentile), but a public vendor advisory/PoC (GHSA-rqh4-rxw3-93rp) is available.

What to do: Upgrade Flowise to 3.1.3 or later as described in the vendor advisory (GHSA-rqh4-rxw3-93rp), prioritizing internet-exposed instances. Until patched, restrict which authenticated users can execute custom JavaScript and upload files to the document store, since exploitation requires valid credentials. Verify your currently deployed version before upgrading to confirm whether you are below 3.1.3.