CVE-2026-56277
mediumpriority · track · 26EPSS 0.002 · 7 %ileDEEUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.7–6.9
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1554Flowise: Mehrere Schwachstellen ermöglichen CodeausführungDeutsch2026-05-14csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Flowise ausnutzen, um Code auszuführen, Objekte anderer Benutzer zu übernehmen, Informationen offenzulegen und weitere, nicht näher genannte Auswirkungen zu erzielen.
- GHSA-m837-xvxr-vqwgFlowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage2026-05-20ghsa · osvUS
### 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 ```typescript // 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: ```typescript // 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.ts` line 83
also known as (3)
Other names and identifiers for this entity.
sources
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references (6)
External citations — patches, advisories, analysis.
- https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-m837-xvxr-vqwgcnnvd
- https://www.vulncheck.com/advisories/flowise-hardcoded-cors-wildcard-in-tts-endpointcnnvd
- https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-m837-xvxr-vqwgenisa_euvd
- https://www.vulncheck.com/advisories/flowise-hardcoded-cors-wildcard-in-tts-endpointenisa_euvd
- https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-m837-xvxr-vqwgMitigationVendor Advisorynvd
- https://www.vulncheck.com/advisories/flowise-hardcoded-cors-wildcard-in-tts-endpointThird Party Advisorynvd
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