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Fencer Intel
critical 9.8

CVE-2026-56271 json

Flowise - Weak Default JWT Secrets in Authentication Middleware

published 6mo ago modified 17d ago also GHSA-cc4f-hjpj-g9p8 , EUVD-2026-43228

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 51%
public exploits
0
none known

Summary

Flowise before 3.1.0 (affected versions 3.0.13 and earlier) uses weak hardcoded default JWT secrets ('auth_token', 'refresh_token') and default audience and issuer values ('AUDIENCE', 'ISSUER') in the enterprise passport authentication middleware (packages/server/src/enterprise/middleware/passport/index.ts). When the corresponding environment variables (JWT_AUTH_TOKEN_SECRET, JWT_REFRESH_TOKEN_SECRET, JWT_AUDIENCE, JWT_ISSUER) are not set, the application silently falls back to these publicly known defaults, allowing an attacker to forge valid JWTs and impersonate any user, including administrators, resulting in authentication bypass.

Patch / fix

  • npm flowise 3.1.0
  • Flowise Flowise 3.1.0

Is CVE-2026-56271 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
3mo ago

Exploit prediction

0.66% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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
GitHub 3.1 5.6 CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm flowise
<3.1.0
3.1.0

Affected products

  • Flowise Flowise

Classification

Weakness
  • CWE-321 Use of Hard-coded Cryptographic Key
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.