Summary
Flowise contains an authentication bypass vulnerability that allows an unauthenticated attacker to obtain OAuth 2.0 access tokens associated with a public chatflow.
By accessing a public chatflow configuration endpoint, an attacker can retrieve internal workflow data, including OAuth credential identifiers, which can then be used to refresh and obtain valid OAuth 2.0 access tokens without authentication.
Details
Flowise is designed to allow public chatflows to be accessed by unauthenticated end users via public URLs or embedded widgets. As a result, chatflowId values are intentionally exposed to unauthenticated clients and must not be treated as secrets.
However, the endpoint GET /api/v1/public-chatbotConfig/<chatflowId> returns internal flowData without authentication. The returned flowData includes workflow node definitions containing OAuth credential identifiers (credential field).
Separately, the endpoint POST /api/v1/oauth2-credential/refresh/<credentialId> allows OAuth. 2.0 tokens to be refreshed without authentication or authorization checks.
Because credential identifiers can be obtained from the unauthenticated public chatflow configuration endpoint, these two behaviors can be combined to allow unauthenticated OAuth 2.0 access token disclosure.
PoC
Prerequisites
- Self-hosted Flowise instance
- A public chatflow configured with an OAuth 2.0 credential (e.g., Gmail OAuth2)
Step 1: Obtain chatflowId
The chatflowId is exposed to unauthenticated users via public chatflow URLs, embedded widgets, or browser network requests when accessing a public chatflow.
Example: d37b9812-72c1-4c64-b152-665f307f755e
Step 2: Retrieve internal flowData without authentication
curl -s \
http://localhost:3000/api/v1/public-chatbotConfig/d37b9812-72c1-4c64-b152-665f307f755e
The response includes flowData containing an OAuth credential identifier, for example:
"credential": "6efe0e20-ba6f-4fbb-9960-658feffa0542"
Step 3: Refresh OAuth 2.0 token without authentication
curl -X POST \
http://localhost:3000/api/v1/oauth2-credential/refresh/6efe0e20-ba6f-4fbb-9960-658feffa0542
The response returns valid OAuth 2.0 access token data, including an access_token.
Impact
An unauthenticated attacker can obtain OAuth 2.0 access tokens for third-party services configured in Flowise, potentially leading to unauthorized data access, API abuse, or account compromise.
This vulnerability affects self-hosted deployments because public chatflows are commonly exposed to the internet and require unauthenticated access by design. Treating chatflowId as a secret does not mitigate the issue.
A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.
CVE-2026-41273 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.1.0); upgrading removes the vulnerable code path.
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.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-41273? CVE-2026-41273 is a high-severity missing authentication for critical function vulnerability in flowise (npm), affecting versions <= 3.0.13. It is fixed in 3.1.0. A critical operation is accessible without requiring any authentication.
- How severe is CVE-2026-41273? CVE-2026-41273 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of flowise are affected by CVE-2026-41273? flowise (npm) versions <= 3.0.13 is affected.
- Is there a fix for CVE-2026-41273? Yes. CVE-2026-41273 is fixed in 3.1.0. Upgrade to this version or later.
- Is CVE-2026-41273 exploitable, and should I be worried? Whether CVE-2026-41273 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 CVE-2026-41273 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 CVE-2026-41273? Upgrade
flowiseto 3.1.0 or later.