GHSA-m837-xvxr-vqwg CVE-2026-56277
Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.18%
- Chance of exploitation in the next 30 days. Higher than 7.50% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains
- Fix
3.1.2- Upgrade flowise to this version or later
Description
Summary
The TTS generation endpoint sets Access-Control-Allow-Origin: * as a hardcoded response header, independent of the server's CORS configuration. This enables any webpage to make cross-origin requests to generate speech using stored credentials.
Root Cause
// packages/server/src/controllers/text-to-speech/index.ts:83
res.setHeader('Access-Control-Allow-Origin', '*')
res.setHeader('Access-Control-Allow-Headers', 'Cache-Control')
Impact
- Cross-origin credential abuse — any webpage can trigger TTS using stored credentials
- Bypasses the server's CORS policy (
getCorsOptions()) which is otherwise restrictive by default - Combined with Finding 3 (TTS credential abuse), enables drive-by credential abuse via malicious webpages
Suggested Fix
Remove the hardcoded CORS wildcard and let the server's CORS middleware handle the headers:
// Remove these lines:
// res.setHeader('Access-Control-Allow-Origin', '*')
// res.setHeader('Access-Control-Allow-Headers', 'Cache-Control')
References
packages/server/src/controllers/text-to-speech/index.tsline 83
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| flowise | < 3.1.2 |
3.1.2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
flowise npm → 3.1.2
- npm
npm install flowise@3.1.2- yarn
yarn add flowise@3.1.2- pnpm
pnpm add flowise@3.1.2
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- Low
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Weakness
CWE-942: Permissive Cross-domain Security Policy with Untrusted Domains
The product uses a web-client protection mechanism such as a Content Security Policy (CSP) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate.
How to prevent it
- Architecture and Design, Operation: Define a restrictive Content Security Policy [REF-1486] or cross-domain policy file.
- Architecture and Design, Operation: Avoid using wildcards in the CSP / cross-domain policy file. Any domain matching the wildcard expression will be implicitly trusted, and can perform two-way interaction with the target server.
- Architecture and Design, Operation: For Flash, modify crossdomain.xml to use meta-policy options such as 'master-only' or 'none' to reduce the possibility of an attacker planting extraneous cross-domain policy files on a server.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-w7x8-q2gp-5cgg Flowise Prompt Injection to RCE and SSRF via CSV/Airtable Agent Python Validator Bypass | Critical | Also affects flowise |
| GHSA-9gvv-qjj3-2p6g Flowise NodeVM sandbox escape via puppeteer allowlist - authenticated RCE and arbitrary file read via Chromium | High | Also affects flowise |
| GHSA-qgvm-j2hm-6m38 Flowise: Unauthenticated OAuth2 token refresh endpoint returns access tokens — enables token theft for any connected service | Critical | Also affects flowise |
| GHSA-5xvg-pmgg-3mxr Flowise: CSV Agent Prompt Injection Remote Code Execution Vulnerability | Critical | Also affects flowise |
| GHSA-gmmw-qg98-6j6p Flowise: Broken Access Control in Stripe Subscription Endpoints Allows Cross-Tenant Billing Manipulation | High | Also affects flowise |
| GHSA-8gj2-2cvc-6xx7 Flowise: Unauthenticated Credential Abuse via Text-to-Speech Endpoint Allows Unauthorized Use of Private Chatflow TTS Credentials | Medium | Also affects flowise |
| GHSA-fm2f-4339-4p2f Flowise: Missing Authorization on Execution Update Endpoint | Medium | Also affects flowise |
| GHSA-wch5-xp77-fxg4 Flowise: Cross-Workspace OAuth2 Credential Metadata Leak | High | Also affects flowise |
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