9.3
CRITICAL CVSS 4.0
CVE-2026-56278
Flowise - Session Hijacking via Weak Default Express Session Secret
Description

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.

INFO

Published Date :

June 30, 2026, 10:08 p.m.

Last Modified :

June 30, 2026, 10:08 p.m.

Remotely Exploit :

Yes !

Source :

VulnCheck
Affected Products

The following products are affected by CVE-2026-56278 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 CRITICAL 83251b91-4cc7-4094-a5c7-464a1b83ea10
Solution
Update Flowise to a version that uses strong, unique secrets for session management.
  • Update Flowise to version 3.1.0 or later.
  • Set a strong, unique EXPRESS_SESSION_SECRET environment variable.
  • Restart the Flowise application after changes.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-56278 vulnerability anywhere in the article.

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.