CVE-2026-34237
CVE-2026-34237 is a medium-severity vulnerability in Lfprojects Mcp Java Sdk with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-942.
Key facts
- Severity: Medium (CVSS 3.x base score 6.1)
- EPSS exploit prediction: 0% (13th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-17496
- Weakness: CWE-942
- Affected product: Lfprojects Mcp Java Sdk
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-34237?
- 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.
- How severe is CVE-2026-34237?
- CVE-2026-34237 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
- Is CVE-2026-34237 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-34237?
- CVE-2026-34237 primarily affects Lfprojects Mcp Java Sdk. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-34237?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-34237 have an EU (EUVD) identifier?
- Yes. CVE-2026-34237 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17496.
- When was CVE-2026-34237 published?
- CVE-2026-34237 was published on 2026-03-31 and last updated on 2026-06-17.
References
- 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
- https://github.com/modelcontextprotocol/java-sdk/security/advisories/GHSA-hv2w-8mjj-jw22
Affected products (2)
- cpe:2.3:a:lfprojects:mcp_java_sdk:*:*:*:*:*:*:*:*
- cpe:2.3:a:lfprojects:mcp_java_sdk:1.1.0:*:*:*:*:*:*:*
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