CVE-2026-45609

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.

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

CVE-2026-45609 has a CVSS score of 7.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.1.9); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-45609? CVE-2026-45609 is a high-severity server-side request forgery (SSRF) vulnerability in org.springaicommunity:mcp-client-security (maven), affecting versions < 0.1.9. It is fixed in 0.1.9. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
2. How severe is CVE-2026-45609? CVE-2026-45609 has a CVSS score of 7.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of org.springaicommunity:mcp-client-security are affected by CVE-2026-45609? org.springaicommunity:mcp-client-security (maven) versions < 0.1.9 is affected.
4. Is there a fix for CVE-2026-45609? Yes. CVE-2026-45609 is fixed in 0.1.9. Upgrade to this version or later.
5. Is CVE-2026-45609 exploitable, and should I be worried? Whether CVE-2026-45609 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45609 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45609? Upgrade org.springaicommunity:mcp-client-security to 0.1.9 or later.