CVE-2026-70478: Flowise Unauthenticated OAuth2 Token Refresh Endpoint Vulnerability

CRITICAL
Advisory Identifier: GHSA-qgvm-j2hm-6m38
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CWE-200
Published
Advisory Summary

CVE-2026-70478 is a CRITICAL unauthenticated oauth2 token refresh endpoint vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Flowise libraries in the npm ecosystem. The issue involves unauthenticated oauth2 token refresh endpoint returns access tokens — enables token theft for any connected service. Remediation is available by upgrading affected packages to version 3.1.3.

CVE-2026-70478 at a Glance

CVE Identifier CVE-2026-70478
GHSA Identifier GHSA-qgvm-j2hm-6m38
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Flowise
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-70478

To remediate this vulnerability, upgrade all affected Flowise dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

flowise fixed: 3.1.3 
npm install flowise@3.1.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls flowise

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-70478, inspect your project dependencies using npm:

npm ls flowise

Analyze the terminal output to locate any version of Flowise in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.1.3), your application is affected.

Note: The npm ls flowise command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In Flowise, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary The OAuth2 token refresh endpoint (`POST /api/v1/oauth2-credential/refresh/:credentialId`) is in `WHITELIST_URLS`, meaning it requires **no authentication**. It decrypts the stored credential (containing `clientId`, `clientSecret`, `refresh_token`), sends a refresh request to the configured OAuth provider, and returns the new `access_token` directly in the response body. ### Root Cause ```typescript // packages/server/src/routes/oauth2/index.ts:393-402 res.json({ success: true, message: 'OAuth2 token refreshed successfully', credentialId: credential.id, tokenInfo: { ...tokenData, // ← includes access_token! has_new_refresh_token: !!tokenData.refresh_token, expires_at: updatedCredentialData.expires_at } }) ``` Whitelist entry at `packages/server/src/utils/constants.ts:40`. ### Attack Chain 1. Attacker obtains a credential ID (via Finding 2 / public chatflow leak, or enumeration) 2. Attacker calls `POST /api/v1/oauth2-credential/refresh/:credentialId` (no auth required) 3. Server decrypts credential, sends refresh request to OAuth provider with user's `client_secret` 4. Server returns the new `access_token` in the response to the attacker 5. Attacker uses the token to access the victim's connected service (Google, Microsoft, etc.) ### Docker Validation `POST /api/v1/oauth2-credential/refresh/fake-uuid` returns `{"message":"Credential not found"}` (not 401 Unauthorized), proving the endpoint processes the request without authentication. ### Impact - OAuth2 access token theft for any connected service - Full access to the victim's third-party accounts (Google, Microsoft, GitHub, etc.) - Client secret transmitted to OAuth provider during refresh - Can also be used for DoS by exhausting refresh token quota ### Suggested Fix Remove the refresh endpoint from `WHITELIST_URLS` and require authentication: ```typescript // Remove from WHITELIST_URLS in constants.ts // Add authentication check in the route handler ``` --- ## Credits - Shinobi Security - https://github.com/shinobisecurity

CVE-2026-70478 Affected Flowise Versions

1 component(s)
Fixed Versions:
3.1.3
Product / Package Ecosystem Affected Versions Fixed Version
flowise
npm/flowise
npm
< 3.1.3
3.1.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-qgvm-j2hm-6m38
Flowise Source Repository REPOSITORY
https://github.com/FlowiseAI/Flowise

Frequently Asked Questions

What is CVE-2026-70478?
CVE-2026-70478 is a security vulnerability in Flowise involving Unauthenticated OAuth2 token refresh endpoint returns access tokens — enables token theft for any connected service under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Flowise versions are affected?
Affected versions include releases prior to 3.1.3 across affected packages: flowise.
What version fixes CVE-2026-70478?
Upgrading to 3.1.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is flowise affected?
Yes, flowise is affected in releases prior to 3.1.3. Upgrade your dependency to 3.1.3 or later.
What CWE is associated with CVE-2026-70478?
CVE-2026-70478 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check npm dependencies for CVE-2026-70478?
Run the dependency tree command: 'npm ls flowise'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-qgvm-j2hm-6m38",
  "modified" : "2026-08-04T19:37:36Z",
  "published" : "2026-08-04T19:37:36Z",
  "aliases" : [ "CVE-2026-70478" ],
  "summary" : "Flowise: Unauthenticated OAuth2 token refresh endpoint returns access tokens — enables token theft for any connected service",
  "details" : "### Summary\n\nThe OAuth2 token refresh endpoint (`POST /api/v1/oauth2-credential/refresh/:credentialId`) is in `WHITELIST_URLS`, meaning it requires **no authentication**. It decrypts the stored credential (containing `clientId`, `clientSecret`, `refresh_token`), sends a refresh request to the configured OAuth provider, and returns the new `access_token` directly in the response body.\n\n### Root Cause\n\n```typescript\n// packages/server/src/routes/oauth2/index.ts:393-402\nres.json({\n    success: true,\n    message: 'OAuth2 token refreshed successfully',\n    credentialId: credential.id,\n    tokenInfo: {\n        ...tokenData,  // ← includes access_token!\n        has_new_refresh_token: !!tokenData.refresh_token,\n        expires_at: updatedCredentialData.expires_at\n    }\n})\n```\n\nWhitelist entry at `packages/server/src/utils/constants.ts:40`.\n\n### Attack Chain\n\n1. Attacker obtains a credential ID (via Finding 2 / public chatflow leak, or enumeration)\n2. Attacker calls `POST /api/v1/oauth2-credential/refresh/:credentialId` (no auth required)\n3. Server decrypts credential, sends refresh request to OAuth provider with user's `client_secret`\n4. Server returns the new `access_token` in the response to the attacker\n5. Attacker uses the token to access the victim's connected service (Google, Microsoft, etc.)\n\n### Docker Validation\n\n`POST /api/v1/oauth2-credential/refresh/fake-uuid` returns `{\"message\":\"Credential not found\"}` (not 401 Unauthorized), proving the endpoint processes the request without authentication.\n\n### Impact\n\n- OAuth2 access token theft for any connected service\n- Full access to the victim's third-party accounts (Google, Microsoft, GitHub, etc.)\n- Client secret transmitted to OAuth provider during refresh\n- Can also be used for DoS by exhausting refresh token quota\n\n### Suggested Fix\n\nRemove the refresh endpoint from `WHITELIST_URLS` and require authentication:\n\n```typescript\n// Remove from WHITELIST_URLS in constants.ts\n// Add authentication check in the route handler\n```\n\n---\n\n## Credits\n\n- Shinobi Security - https://github.com/shinobisecurity",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "flowise"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.1.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.1.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-qgvm-j2hm-6m38"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/FlowiseAI/Flowise"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-04T19:37:36Z",
    "nvd_published_at" : null
  }
}