CVE-2026-56278

critical · 9.3

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.

9.3

CVSS

0.5%

EPSS (exploit prob.)

44th

EPSS percentile

2026-06-30

Published

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-798

Affected products

Vendor	Product	Affected versions
flowiseai	flowise	< 3.1.0

Check a specific version with /api/v1/cve/match.

References

https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-2qqc-p94c-hxwh
https://www.vulncheck.com/advisories/flowise-session-hijacking-via-weak-default-express-session-secret

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-56278