Vulnerability · Published Oct 27, 2026 · Assigned by AMZN

CVE-2026-115413AWS API MCP Server OAuth Token Audience Validation Bypass

High 7.8

In plain English

A high-severity security flaw in aws-api-mcp-server from AWS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities).

Severity (CVSS 3.1)7.8High

Exploit odds (30 days)<0.1%top 99.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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 products (as reported)

Vendor	Product	Versions
AWS	aws-api-mcp-server	1.3.0 – before 1.6.0

Weakness: CWE-346 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

https://pypi.org/project/awslabs.aws-api-mcp-server/1.6.0/ release-notes, patch
https://github.com/awslabs/mcp/security/advisories/GHSA-4prq-p2x5-w9fh third-party-advisory
https://aws.amazon.com/security/security-bulletins/2026-152-aws/ vendor-advisory