Vulnerability in Flowise
CVE-2026-56278
Flowise before 3.1.0 (affected versions 3.0.13 and earlier) uses a weak hardcoded default secret ('flowise') for the express-session middleware when the EXPRESS_SESSION_SECRET environment variable is not set (packages/server/src/enterprise/middleware/passport/index.ts). Because this default secret is publicly visible in the source code, an attacker can forge valid signed session cookies to impersonate any user and bypass authentication.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (42.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Flowise — versions 0, 3.1.0
- Flowiseai Flowise
Weakness classification (CWE)
References
- github.com/FlowiseAI/Flowise/security/advisories/GHSA-2qqc-p94c-hxwh (vendor-advisory, Mitigation, Vendor Advisory)
- www.vulncheck.com/advisories/flowise-session-hijacking-via-weak-default-express… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-56278?
- CVE-2026-56278 is a critical-severity vulnerability in Flowise, classified under Use of Hard-coded Credentials. CVSS score: 9.1/10. Published 2026-06-30.
- How severe is CVE-2026-56278?
- Critical severity. CVSS v3 base score is 9.1 out of 10.