CVE-2026-100307: Amazon mcp-gateway-registry authorization bypass in management API

CVE-2026-100307 · Severity: high · CVSS 8.8 · Published 2026-11-11

Amazon mcp-gateway-registry is a registry and gateway for Model Context Protocol servers that manages discovery and access control for gateway assets. An authenticated user without administrative privileges can exploit a missing authorization check in the management API to grant themselves registry administrator access, gaining full control over all registered gateway assets and the ability to read stored credentials.

Technologies: Amazon AWS, Amazon Mcp-Gateway-Registry. Vendors: Amazon.

Quick answers

Is CVE-2026-100307 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-100307 being exploited in the wild.
How severe is CVE-2026-100307?
High severity, with a CVSS score of 8.8, published 11 November 2026.
Which products and versions are affected?
Amazon Mcp-Gateway-Registry 1.0.9 through 1.24.7.
Is there a fix for CVE-2026-100307?
Yes: fixed in 1.25.0. Until then: Restrict access to POST /api/servers/groups/* and related /api/servers/* mutation routes at the ingress layer to trusted administrator identities only. Monitor the mcp_scopes DocumentDB collection for unexpected changes to group_mappings and ui_permissions. Review application HTTP logs for POST /api/servers/groups/import requests from non-administrator accounts. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-100307 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-100307?
Check whether you run Amazon AWS or Amazon Mcp-Gateway-Registry at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Fixed in: 1.25.0

Restrict access to POST /api/servers/groups/* and related /api/servers/* mutation routes at the ingress layer to trusted administrator identities only. Monitor the mcp_scopes DocumentDB collection for unexpected changes to group_mappings and ui_permissions. Review application HTTP logs for POST /api/servers/groups/import requests from non-administrator accounts.

Technical details

The external management API endpoints (/api/servers/*) perform authentication but lack role-based authorization checks. A low-privileged authenticated user can submit a crafted group import request to POST /api/servers/groups/import that maps their identity provider group to the mcp-registry-admin scope, achieving privilege escalation without re-authentication. The vulnerability affects versions 1.0.9 through 1.24.7 and is fixed in version 1.25.0.

Affected products

  • Amazon mcp-gateway-registry 1.0.9 through 1.24.7

Timeline

  • 2026-11-11: disclosed
  • 2026-06-27: patched

References

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