CVE-2026-34237
MCP Java SDK has a Hardcoded Wildcard CORS (Access-Control-Allow-Origin: *)
- State
- Published
- Severity
- 6.1 Medium
- Published
- Mar 31, 2026
- Updated
- Jun 9, 2026
- Reserved
- Mar 26, 2026
Description
MCP Java SDK is the official Java SDK for Model Context Protocol servers and clients. Prior to versions 0.83.0, 1.0.1, and 1.1.1, there is a hardcoded wildcard CORS vulnerability. This issue has been patched in versions 0.83.0, 1.0.1, and 1.1.1.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.1 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | GitHub_M |
Weaknesses
- CWE-942 Permissive Cross-domain Policy with Untrusted Domains
Affected Products
| Product | Versions |
|---|---|
java-sdkmodelcontextprotocol |
|
References
- https://github.com/modelcontextprotocol/java-sdk/security/advisories/GHSA-hv2w-8mjj-jw22
- https://github.com/modelcontextprotocol/java-sdk/blob/main/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java#L289
- https://github.com/modelcontextprotocol/java-sdk/blob/main/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java#L525
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.