CVE-2026-115413: AWS API MCP Server OAuth Token Audience Validation Bypass
Missing token audience validation in the OAuth authentication mode of AWS API MCP Server before version 1.6.0 might allow local users to run AWS operations with the server's configured AWS credentials via an access token issued to another application by the same identity provider.
To remediate this issue, users should upgrade to version 1.6.0 and configure the expected token audience or client ID for the server.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
AWS API MCP Serverto a version that resolves this vulnerability.Fixed in 1.6.0 - Configuration
Configure the server with the expected token audience or client ID.
AWS API MCP Server OAuth authentication expected token audience or client ID = configured expected token audience or client ID
Event History
Frequently Asked Questions
Who is exposed to this issue?
AWS API MCP Server deployments using OAuth authentication before version 1.6.0 are affected. Exploitation requires a local user and an access token issued by the same identity provider for a different application.
What access could an attacker obtain?
A local attacker may be able to run AWS operations using the AWS credentials configured on the server. The impact includes potential disclosure, modification, and disruption of resources accessible through those credentials.
What should be configured after upgrading?
Upgrade to version 1.6.0 and configure the expected token audience or client ID for the server. This ensures tokens issued for other applications are not accepted by the server.
What is the immediate mitigation if an upgrade cannot be completed?
The provided remediation specifies upgrading to version 1.6.0 and configuring the expected token audience or client ID. No alternative workaround is provided.