MCP Java SDK has a Hardcoded Wildcard CORS (Access-Control-Allow-Origin: *)
Priority LOW 27CWE-942Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00231 14th percentileScored 2026-11-07
Fix Fixed java-sdk (modelcontextprotocol): 1.0.1, 1.1.1, 0.18.3io.modelcontextprotocol.sdk:mcp-core (Maven): 1.0.1, 1.1.1, 0.18.3
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| MLflow | java-sdk | 1.0.0 to before 1.0.1; 1.1.0 to before 1.1.1; before 0.18.3 | 1.0.1, 1.1.1, 0.18.3 | Patch available | CNA |
| — | io.modelcontextprotocol.sdk:mcp-core (Maven) | 1.0.0 to before 1.0.1 | 1.0.1 | Patch available | GHSA-hv2w-8mjj-jw22 |
| — | io.modelcontextprotocol.sdk:mcp-core (Maven) | 1.1.0 to before 1.1.1 | 1.1.1 | Patch available | GHSA-hv2w-8mjj-jw22 |
| — | io.modelcontextprotocol.sdk:mcp-core (Maven) | before 0.18.3 | 0.18.3 | Patch available | GHSA-hv2w-8mjj-jw22 |
- java-sdk VendorMLflow Affected 1.0.0 to before 1.0.1; 1.1.0 to before 1.1.1; before 0.18.3 Fixed in 1.0.1, 1.1.1, 0.18.3 Patch available CNA
- io.modelcontextprotocol.sdk:mcp-core (Maven) Vendor— Affected 1.0.0 to before 1.0.1 Fixed in 1.0.1 Patch available GHSA-hv2w-8mjj-jw22
- io.modelcontextprotocol.sdk:mcp-core (Maven) Vendor— Affected 1.1.0 to before 1.1.1 Fixed in 1.1.1 Patch available GHSA-hv2w-8mjj-jw22
- io.modelcontextprotocol.sdk:mcp-core (Maven) Vendor— Affected before 0.18.3 Fixed in 0.18.3 Patch available GHSA-hv2w-8mjj-jw22
Remediation
- Fix · CNA java-sdk (modelcontextprotocol) Fixed in 1.0.1, 1.1.1, 0.18.3
- Fix · GHSA-hv2w-8mjj-jw22 io.modelcontextprotocol.sdk:mcp-core (Maven) Fixed in 1.0.1 Advisory →
- Fix · GHSA-hv2w-8mjj-jw22 io.modelcontextprotocol.sdk:mcp-core (Maven) Fixed in 1.1.1 Advisory →
- Fix · GHSA-hv2w-8mjj-jw22 io.modelcontextprotocol.sdk:mcp-core (Maven) Fixed in 0.18.3 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-34237
- 2026-10-03 Alias added: GHSA-hv2w-8mjj-jw22
References
Patch 2
- 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
Advisory 2
More MLflow Mcp Java Sdk vulnerabilities
- TI-2026-27672 MCP Java-SDK has a DNS Rebinding Vulnerability CVSS 4.0HIGH 7.6
Sources
- CVE-2026-34237 · CVE Program
- CVE-2026-34237 · NVD
- FIRST EPSS
- GHSA-hv2w-8mjj-jw22 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences