Improper handling of an initialization failure in AWS API MCP Server from 0.2.13 through 1.3.46 might allow an actor to bypass the user-configured security policy and execute AWS API operations that the policy was set to deny or gate. When initialization of the security policy enforcement data fails at server startup, the policy check is skipped for the lifetime of the process. IAM permissions on the configured credentials remain in effect and are unaffected.
To remediate this issue, users should upgrade to version 1.3.47.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://aws.amazon.com/security/security-bulletins/2026-063-aws/
ff89ba41-3aa1-4d27-914a-91399e9639e5
https://github.com/awslabs/mcp/security/advisories/GHSA-29w2-fq35-v728
ff89ba41-3aa1-4d27-914a-91399e9639e5
https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.47/
ff89ba41-3aa1-4d27-914a-91399e9639e5