CVE-2026-16584 aws-api-mcp-server vulnerability
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.
Browse API Security security risksQuick answer
aws-api-mcp-server should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- < 1.3.47
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
CVE-2026-16584 affects aws-api-mcp-server and involves authorization failure. Successful exploitation may let a lower-privileged user view or change data outside their allowed scope. Prioritize internet-facing, privileged, automation, and production deployments. Upgrade aws-api-mcp-server to 1.3.47 or a later vendor-supported fixed release.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses aws-api-mcp-server.
- Compare the installed version with the recorded affected range: < 1.3.47.
- Upgrade aws-api-mcp-server to 1.3.47 or a later vendor-supported fixed release.
- Until patched, restrict the affected API or workflow to trusted administrators and enforce an additional access-control layer at the proxy or network boundary.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to aws-api-mcp-server; remove access that is not required.
- Review authentication, API, audit, and object-change logs for cross-user access, bypassed checks, or unexpected privileged actions.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
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Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-16584 in place.
- Use a safe regression test to confirm the affected authorization failure path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2026-16584?
aws-api-mcp-server versions listed as affected should be reviewed: < 1.3.47.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.