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.

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.

EPSS: 0.004 (29.3th percentile) — read the EPSS interpretation.

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.

Affected products

Flowise — versions 0, 3.1.0
Flowiseai Flowise

Weakness classification (CWE)

CWE-798 — Use of Hard-coded Credentials

References

disclosure@vulncheck.com (vendor-advisory, Mitigation, Vendor Advisory)
disclosure@vulncheck.com (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.