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CVE-2026-34237

MCP Java SDK has a Hardcoded Wildcard CORS (Access-Control-Allow-Origin: *)

Published: Mar 31, 2026Updated: Jun 9, 2026 Sources: CVE List NVDCWE-942
NVD MITRE
6.1CVSSMEDIUM
EPSS Score
0.2%
Top 87.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:CC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-942

Affected Products

mcp java sdklfprojects
Mixed
AI / ML / notebook-mlops
java-sdkmodelcontextprotocol
Mixed
AI / ML / ai-agent-tooling
lfprojectsoss-projectAI / MLaka mlflow, valkey, model context protocol servers, mcp servers
modelcontextprotocoloss-projectAI / MLaka mcp, model context protocol

Exploitability

Official Patch Available
Workaround Available

References

https://github.com/modelcontextprotocol/java-sdk/blob/main/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletSseServerTransportProvider.java#L289
github.com
https://github.com/modelcontextprotocol/java-sdk/blob/main/mcp-core/src/main/java/io/modelcontextprotocol/server/transport/HttpServletStreamableServerTransportProvider.java#L525
github.com
https://github.com/modelcontextprotocol/java-sdk/security/advisories/GHSA-hv2w-8mjj-jw22
github.com

Timeline

Published
Mar 31, 2026
Last Updated
Jun 9, 2026

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