If your company is using Flowise to build AI-powered tools, a newly disclosed security flaw could let an attacker quietly reach inside your private network and walk away with the keys to your cloud infrastructure — all without ever breaking down the front door.
Who's Affected, and Why It Matters
Flowise has become one of the most popular open-source tools for building custom AI workflows. Companies, developers, and startups use it to visually wire together large language models — think ChatGPT-style bots, document analyzers, customer service agents — without writing a mountain of code. Its drag-and-drop simplicity has earned it over 35,000 GitHub stars and a place in countless enterprise and startup AI stacks worldwide.
The vulnerability, tracked as CVE-2026-41270 and rated HIGH severity, affects every version of Flowise prior to 3.1.0. If your organization self-hosts Flowise — which many do, precisely because it processes sensitive business data — and you haven't updated, your internal network may be reachable by anyone with a login to your Flowise instance. That includes contractors, junior developers, or anyone whose credentials have been compromised.
What's Actually Happening — No Jargon Required
Think of your company's internal network like a walled office building. Outside the walls is the public internet. Inside are the really sensitive things: servers that manage your databases, internal APIs, and — critically — a special intercom system used by cloud providers like AWS, Google Cloud, and Azure. That intercom (technically called a "metadata service") will hand out powerful access credentials to anyone standing inside the building who asks nicely.
Flowise knew this was a risk, so they built a bouncer at the gate — a blocklist that stops the application from making unauthorized trips to those sensitive internal addresses. The problem is, the bouncer only checks certain paths into the building. Flowise's "Custom Function" feature — which lets users run their own code snippets inside the platform — uses a sandboxed environment that restricts most dangerous behaviors. But the sandbox forgot to put a bouncer on a different set of doors: the ones built directly into the underlying Node.js programming language itself. An attacker who knows about these unguarded doors can simply walk through them instead.
In practice, this means a malicious — or simply curious — authenticated user can write a small custom function, point it at the cloud metadata address (169.254.169.254, a well-known internal IP used by AWS and others), and receive back live credentials that could grant sweeping access to your cloud environment. From there, the blast radius expands fast: data exfiltration, privilege escalation, or full cloud account takeover are all on the table.
The Technical Detail Security Teams Need
The root cause is a sandbox escape via unprotected Node.js built-in modules. Flowise's SSRF protection is enforced at the HTTP client library level — blocking dangerous outbound requests through axios and node-fetch — but the NodeVM sandbox grants direct access to Node's native http, https, and net modules without routing those requests through any equivalent deny-list check. This is a classic case of defense at the wrong abstraction layer: the protection lives in the library, not the network, so swapping the library sidesteps the protection entirely. The vulnerability carries a CVSS score of 7.1 (HIGH) and falls under the SSRF bypass / sandbox escape vulnerability class.
Real-World Context: Discovered, Not Yet Exploited
As of publication, no active exploitation has been confirmed in the wild. The flaw was responsibly disclosed to the Flowise team and patched in the 3.1.0 release. However, security researchers are urging swift action — and for good reason. Flowise is frequently deployed in environments with direct access to cloud infrastructure, making it a high-value pivot point. The combination of an accessible web UI, user-level authentication requirements (rather than admin-only), and a path to cloud credential theft makes this a prime candidate for inclusion in attacker playbooks once proof-of-concept code circulates publicly, which historically tends to happen within days to weeks of disclosure.
The vulnerability was assigned under coordinated disclosure practices. No specific threat actor group or known victim campaign has been attributed at this time.
What You Should Do Right Now
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Update Flowise to version 3.1.0 or later — immediately. This is the only complete fix. Check your deployment by navigating to your Flowise dashboard and reviewing the version number in the bottom corner, or run
npm list flowisein your deployment directory. If you're running Docker, pull the latest image taggedflowiseai/flowise:3.1.0or higher. - Audit who has authenticated access to your Flowise instance. Because this is an authenticated exploit, the immediate risk comes from inside your user list. Review your Flowise user accounts, revoke any credentials that are unused or belong to former employees, and consider temporarily disabling the Custom Function feature at the application level until you can patch.
- Apply network-level SSRF controls as a defense-in-depth measure. Regardless of patching, configure your cloud security groups, firewall rules, or instance metadata service (IMDS) to require IMDSv2 on AWS (which adds a session-oriented layer of protection), or restrict metadata endpoint access to specific system processes only. On GCP and Azure, equivalent controls exist under their respective identity and metadata service settings. This won't patch the vulnerability, but it raises the bar for any future bypass attempts.
Bottom line: Flowise is a powerful tool sitting close to sensitive infrastructure in a lot of organizations. This flaw doesn't require a sophisticated attacker — just someone with a login and knowledge of a well-documented technique. Patch first, audit second, harden third.