How severe is GHSA-m837-xvxr-vqwg?

No CVSS score has been assigned to GHSA-m837-xvxr-vqwg yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-m837-xvxr-vqwg?

GHSA-m837-xvxr-vqwg affects the following packages: flowise (npm). Ecosystems affected: npm.

How do I fix GHSA-m837-xvxr-vqwg?

Update flowise to 3.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m837-xvxr-vqwg is resolved across your whole dependency graph.

How do I detect GHSA-m837-xvxr-vqwg in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flowise, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-m837-xvxr-vqwg if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-m837-xvxr-vqwg actively exploited in the wild?

No public exploit code has been indexed for GHSA-m837-xvxr-vqwg yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-m837-xvxr-vqwg?

GHSA-m837-xvxr-vqwg has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 7th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-m837-xvxr-vqwg?

GHSA-m837-xvxr-vqwg is classified as CWE-346 (CWE-346). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-m837-xvxr-vqwg published, and has it been updated?

GHSA-m837-xvxr-vqwg was published on May 20, 2026 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

GHSA-m837-xvxr-vqwg — flowise

GHSA-m837-xvxr-vqwg is a CWE-346 vulnerability in flowise. A fix is available for flowise — see the affected versions and patch details below.

Flowise: Hardcoded CORS wildcard on TTS endpoint enables cross-origin credential abuse from any webpage

Also known asCVE-2026-56277

Published

May 20, 2026

Updated

Jul 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 30, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-m837-xvxr-vqwg.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs7th percentile — riskier than 7% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

flowisenpm

3Kdownloads / week

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.ts line 83

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`flowise`	all versions	3.1.2`npm install flowise@3.1.2`

Affected Products

1 product · 1 configurations

Application

flowiseflowiseai

< 3.1.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flowise, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update flowise to 3.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m837-xvxr-vqwg is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### 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 po

O3 Security · Impact-Aware SCA

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