GHSA-QJP4-4JVR-XQG3

Vulnerability from github – Published: 2026-05-18 13:29 – Updated: 2026-05-18 13:29
VLAI
Summary
Spring AI MCP Security: Unvalidated URL Fetching (SSRF)
Details

Summary

The mcp-security framework fails to implement the mandatory SSRF mitigations outlined in the Model Context Protocol (MCP) security specifications. Specifically, it processes untrusted URLs for OAuth-related discovery and metadata without verifying if the targets are malicious or internal to the network.

This only affects installations with Dynamic Client Registration (DCR) enabled:

spring.ai.mcp.client.authorization.dynamic-client-registration.enabled=true

DCR does not validate URLs exposed by MCP Servers (protected resource metadata URL, authorization server URL) and Authorization Servers (all OAuth2 endpoints).

Workaround

When users need to perform DCR, they may provide their own McpOAuth2ClientManager. Both McpMetadataDiscoveryService and DynamicClientRegistrationService are also affected, if used, users should provide their own subclasses.

Alternatively, users can provide the default implementations of these classes with a RestClient that implements URL filtering through ClientHttpRequestInterceptor.

Severity
7.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.springaicommunity:mcp-client-security"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.1.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-45609"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-18T13:29:29Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nThe mcp-security framework fails to implement the mandatory SSRF mitigations outlined in the Model Context Protocol (MCP) [security specifications](https://modelcontextprotocol.io/docs/tutorials/security/security_best_practices#mitigation-3). Specifically, it processes untrusted URLs for OAuth-related discovery and metadata without verifying if the targets are malicious or internal to the network.\n\nThis only affects installations with Dynamic Client Registration (DCR) enabled:\n\n```properties\nspring.ai.mcp.client.authorization.dynamic-client-registration.enabled=true\n```\n\nDCR does not validate URLs exposed by MCP Servers (protected resource metadata URL, authorization server URL) and Authorization Servers (all OAuth2 endpoints).\n\n### Workaround\n\nWhen users need to perform DCR, they may provide their own `McpOAuth2ClientManager`. Both `McpMetadataDiscoveryService` and `DynamicClientRegistrationService` are also affected, if used, users should provide their own subclasses.\n\nAlternatively, users can provide the default implementations of these classes with a `RestClient` that implements URL filtering through `ClientHttpRequestInterceptor`.",
  "id": "GHSA-qjp4-4jvr-xqg3",
  "modified": "2026-05-18T13:29:29Z",
  "published": "2026-05-18T13:29:29Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/spring-ai-community/mcp-security/security/advisories/GHSA-qjp4-4jvr-xqg3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/spring-ai-community/mcp-security/pull/68"
    },
    {
      "type": "WEB",
      "url": "https://github.com/spring-ai-community/mcp-security/commit/e6b67d8a67cd7acbee6e4c0741c385d62e3ed576"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/spring-ai-community/mcp-security"
    },
    {
      "type": "WEB",
      "url": "https://github.com/spring-ai-community/mcp-security/releases/tag/v0.1.9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Spring AI MCP Security: Unvalidated URL Fetching (SSRF)"
}


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