CVE-2026-56277
Flowise - Hardcoded CORS Wildcard in TTS Endpoint
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Flowise - Hardcoded CORS Wildcard in TTS Endpoint
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.
- Record
CVE-2026-56277- CVSS 4.0
- 6.9 Medium
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 - Weakness
- CWE-346
- Updated
- 2026-11-02
EUVDEUVD-2026-40432
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.
- Record
EUVD-2026-40432- CVSS 4.0
- 6.9 Medium
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8m62-6r3h-3x25
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to...
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.
- Record
GHSA-8m62-6r3h-3x25- CVSS 4.0
- 6.9 Medium
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/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 - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-346
- Updated
- 2026-11-02
GitHub AdvisoriesGHSA-m837-xvxr-vqwg
Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage
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
- Record
GHSA-m837-xvxr-vqwg- CVSS 4.0
- 6.9 Medium
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 - Weakness
- CWE-942
- Updated
- 2026-11-02
NVD
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.
- Record
CVE-2026-56277- CVSS 4.0
- 6.9 Medium
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/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 - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-346
- Updated
- 2026-11-02
OSV
Flowise - Hardcoded CORS Wildcard in TTS Endpoint
Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.
- Record
CVE-2026-56277- CVSS 4.0
- 6.9 Medium
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 - Weakness
- CWE-346
- Updated
- 2026-11-02
OSVGHSA-m837-xvxr-vqwg
Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage
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
- Record
GHSA-m837-xvxr-vqwg- CVSS 4.0
- 6.9 Medium
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 - Weakness
- CWE-942
- Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-56277 is a medium vulnerability (CVSS 6.9) in Flowise, published May 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.18%, the 7th percentile. Fixed in flowise 3.1.2.
References
github.com/FlowiseAI/Flowise/security/advisories/GHSA-m837-xvxr-vqwg
vulncheck.com/advisories/flowise-hardcoded-cors-wildcard-in-tts-endpoint
nvd.nist.gov/vuln/detail/CVE-2026-56277