CVE-2026-16895
Received Received - Intake

Metasploit Framework JSON-RPC Authentication Bypass via Logic Flaw

Publication date: 2026-08-27

Last updated on: 2026-08-27

Assigner: Rapid7, Inc.

Description
A logic vulnerability (fail-open condition) has been identified within the Metasploit Framework's JSON-RPC web service interface. When an exception occurs during the database health check (db.check) and the environment variable MSF_WS_JSON_RPC_API_TOKEN is not explicitly set, the application resets the internal state flag msf.auth_initialized to false. The ApiToken Warden authentication strategy misinterprets this false value as an indicator that authentication is not initialized or required, thereby granting unauthenticated local access to the JSON-RPC request dispatcher.

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Meta Information

Published
2026-08-27
Last Modified
2026-08-27
Generated
2026-08-27
AI Q&A
2026-08-27
EPSS Evaluated
N/A
NVD
CVE-2026-16895
EUVD
EUVD-2026-66836

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
rapid7 metasploit_framework *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-305 The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.

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Executive Summary

CVE-2026-16895 is a logic vulnerability in Metasploit Framework's JSON-RPC web service interface. When an exception occurs during a database health check and the MSF_WS_JSON_RPC_API_TOKEN environment variable is not set, the application incorrectly resets an authentication flag. This causes the system to mistakenly allow unauthenticated local access to the JSON-RPC request handler.

Detection Guidance

Check if the Metasploit Framework's JSON-RPC web service is running and if authentication is properly enforced. Review logs for unauthenticated JSON-RPC requests or failed database health checks (db.check). Ensure the environment variable MSF_WS_JSON_RPC_API_TOKEN is set to enforce authentication.

Impact Analysis

This vulnerability allows unauthenticated local users to send JSON-RPC requests to the Metasploit Framework. Attackers could exploit this to execute unauthorized commands or interact with the framework's functionality without proper authentication, potentially leading to system compromise or further attacks.

Compliance Impact

This vulnerability allows unauthenticated local access to the Metasploit Framework's JSON-RPC interface due to a logic flaw. This could potentially lead to unauthorized data access or modification, which may violate compliance requirements under GDPR (data protection) or HIPAA (health information security) if exploited in systems handling protected data.

Mitigation Strategies

Update the Metasploit Framework to the latest version to enforce mandatory authentication. Set the MSF_WS_JSON_RPC_API_TOKEN environment variable to a strong token. Disable unauthenticated JSON-RPC access and review authentication logs for suspicious activity.

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