How to meet it
OWASP AISVS v1.01
Model Context Protocol (MCP) Security · Authentication & Authorization
Accept only tokens issued for this server
Verify that MCP servers only accept tokens explicitly issued for them, and do not pass tokens issued for other services through to downstream APIs.
OWASP AISVS v1.01, requirement 10.2.7
In plain English
Accept only tokens issued for this server, and never forward a client's token to another API.
What good looks like
- Tokens with another audience are rejected.
- Downstream calls use tokens obtained for those services.
- Token forwarding is absent from the code.
How teams usually do it
- Audience checks plus token exchange for downstream calls.
Evidence an auditor would accept
- Code review notes and tests.
Common mistakes
- Passing the incoming token straight to a backend API.
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Requirement text from the OWASP AI Security Verification Standard, licensed under CC BY-SA 4.0. This guidance is shared under the same licence.