CVE-2026-56278 — flowise
CVE-2026-56278 is a Hard-coded Credentials vulnerability in flowise. A fix is available for flowise — see the affected versions and patch details below.
Flowise - Session Hijacking via Weak Default Express Session Secret
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-56278.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
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
Detection Method: Kolega.dev Deep Code Scan
| Attribute | Value |
|---|---|
| Location | packages/server/src/enterprise/middleware/passport/index.ts:55 |
| Practical Exploitability | High |
| Developer Approver | [email protected] |
Description
Express session secret has a weak default value 'flowise' when EXPRESS_SESSION_SECRET is not set.
Affected Code
secret: process.env.EXPRESS_SESSION_SECRET || 'flowise'
Evidence
The default session secret 'flowise' is publicly visible and weak. Session cookies signed with this secret can be forged by attackers.
Impact
Session hijacking and forgery - attackers can create arbitrary session cookies to impersonate any user, bypassing all authentication mechanisms.
Recommendation
Require EXPRESS_SESSION_SECRET to be set with a strong random value. Throw an error on startup if not configured. Use cryptographically strong random strings (minimum 256 bits).
Notes
The Express session secret defaults to the string 'flowise' when EXPRESS_SESSION_SECRET is not set (line 55). This secret is used to sign session cookies via express-session middleware. Since 'flowise' is publicly visible in the source code, an attacker can forge valid session cookies to impersonate any user without authentication. The .env.example file has this commented out (# EXPRESS_SESSION_SECRET=flowise), implying it's optional, which compounds the risk. Unlike development-only defaults, this code path is active in production if the environment variable is not set. The application should require EXPRESS_SESSION_SECRET to be explicitly configured with a cryptographically strong random value and fail to start otherwise.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | flowise | all versions | 3.1.0npm install flowise@3.1.0 |
Affected Products
flowiseflowiseaiDetection & 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 3.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56278 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2026-56278 in your dependencies?
Find it across npm, including transitive dependencies.