Flowise EUVD-2026-57806

Requires an authenticated Flowise account (PR:L) with the ability to reach the vulnerable feature over the network and to place a file into the document store; the attacker must craft a fake String object exposing a malicious match function to defeat the path-traversal validation and abuse the moment locale-validation bypass. Limiting factors: exploitation is not fully unauthenticated (a valid low-privileged login is needed), it depends on the vm2-sandboxed code-execution/custom-function functionality being reachable and on write access to the document store, and the AT:P metric reflects the specific crafted-payload requirement - so environments that disable code nodes, forbid document-store writes for untrusted users, or restrict account creation materially reduce realistic exploitability. Affected versions are strictly those before 3.1.3.

This is a genuine priority rather than a paper-high score: the CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:L/UI:N) with H across all vulnerable- and subsequent-system impact metrics describes network-reachable, low-complexity code execution that only requires a low-privileged authenticated account, and a sandbox escape inherently crosses a trust boundary (subsequent-system impact H). The AT:P attack requirement reflects the need to craft a specific fake-String payload and stage a file in the document store, which modestly raises effort but is fully attacker-controlled and deterministic, not a race. Signals are partly incomplete: there is no CISA KEV entry and no confirmed public PoC, so this is not confirmed active exploitation, but VulnCheck's advisory plus a concrete technical description means weaponization is well within reach for a motivated actor. Given that Flowise is often deployed with weak or shared authentication and sometimes exposed to internal or internet-facing networks, even a mid-sized municipal IT team in sanok running a self-hosted Flowise instance should treat this as urgent and patch promptly rather than relying on the authentication requirement as a safeguard. Net assessment: high real-world risk where any semi-trusted user can obtain an account, lower where Flowise is single-tenant and tightly access-controlled.

A user with a low-privileged Flowise account uploads or plants a malicious JavaScript file in the document store, then triggers a workflow that invokes the vulnerable code path with a crafted fake String object whose match function bypasses the path-traversal check. Flowise resolves the path outside the vm2 sandbox and executes the file as the host Node.js process, giving the attacker code execution on the server. No public PoC was identified at time of analysis, but VulnCheck's advisory describes the mechanism in enough detail to reconstruct it.