CVE-2026-45609
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedmcp-security provides Security and Authorization support for Model Context Protocol in Spring AI. Prior to 0.1.9, 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 This vulnerability is fixed in 0.1.9.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe mcp-security framework for Spring AI fails to implement mandatory SSRF mitigations when processing untrusted URLs for OAuth-related discovery and metadata. Specifically, it does not validate whether target URLs are malicious or pointing to internal network resources before making requests. This only affects installations with Dynamic Client Registration (DCR) enabled.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 0.1.0, < 0.1.9CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the installed mcp-security versionInspect your project's dependency management file (pom.xml, build.gradle, package-lock.json, or similar) and locate the 'mcp-security' or 'spring-ai-mcp-security' dependency. Note its exact version number.Affected if The version is 0.1.0 through 0.1.8 (anything less than 0.1.9)
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Determine if Dynamic Client Registration (DCR) is enabledSearch your configuration files (application.yml, application.properties, or any Spring AI/MCP configuration files) for properties such as 'spring.ai.mcp.security.dcr.enabled', 'mcp.security.dcr', 'oauth.dcr.enabled', or similar DCR-related settings. Check for any flag that enables Dynamic Client Registration.Affected if DCR is explicitly enabled (set to true) in your configuration
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Locate OAuth endpoint URLs configured for discovery or metadataReview your configuration for any OAuth-related URLs used during client registration, discovery, or metadata fetching. Look for properties like 'issuer-uri', 'authorization-uri', 'token-uri', 'jwk-set-uri', or custom OAuth endpoint URLs that the framework uses when DCR processes untrusted URLs.Affected if You have OAuth discovery or metadata endpoints configured, especially if they accept values from external or untrusted sources
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Inspect network egress controls for OAuth requestsCheck whether your application has any network filtering, web application firewall (WAF), or API gateway rules that restrict outbound requests from the application server to internal network ranges (127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, etc.). Review any proxy or firewall configuration that might limit where OAuth requests can be sent.Affected if No network egress restrictions exist, allowing the application to make requests to internal or arbitrary network addresses
You are affected if the installed mcp-security version is between 0.1.0 and 0.1.8 AND Dynamic Client Registration is enabled in your configuration, as this combination allows the vulnerable code path to execute SSRF-prone outbound requests.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.1.9
Upgrade mcp-security to version 0.1.9 or later to obtain the SSRF protections. If immediate upgrade is not possible, consider disabling Dynamic Client Registration (DCR) if not required to reduce the attack surface.
0.1.9
- Locate the mcp-security dependency declaration in your project's build configuration (pom.xml for Maven or build.gradle for Gradle)
- Update the version of mcp-security from your current version (< 0.1.9) to version 0.1.9
- Run a dependency update command: `mvn clean compile` for Maven or `./gradlew dependencies` for Gradle to verify the new version is resolved
- Rebuild your application with the updated dependency
- If using Dynamic Client Registration (DCR), test the OAuth discovery and metadata endpoints to confirm functionality still works after the SSRF mitigations are in place
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-45609 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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