Summary
Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage
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')
References
packages/server/src/controllers/text-to-speech/index.tsline 83
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
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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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')
Frequently Asked Questions
- What is GHSA-M837-XVXR-VQWG? GHSA-M837-XVXR-VQWG is a medium-severity security vulnerability in flowise (npm), affecting versions <= 3.1.1. It is fixed in 3.1.2.
- Which versions of flowise are affected by GHSA-M837-XVXR-VQWG? flowise (npm) versions <= 3.1.1 is affected.
- Is there a fix for GHSA-M837-XVXR-VQWG? Yes. GHSA-M837-XVXR-VQWG is fixed in 3.1.2. Upgrade to this version or later.
- Is GHSA-M837-XVXR-VQWG exploitable, and should I be worried? Whether GHSA-M837-XVXR-VQWG is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-M837-XVXR-VQWG is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-M837-XVXR-VQWG? Upgrade
flowiseto 3.1.2 or later.