What’s Vulnerable › Vulnerabilities

CVE-2026-108395: Model Context Protocol Java SDK HTTP server transports allow memory exhaustion through unbounded request bodies

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-14 · updated 2026-10-16
• Weakness: CWE-770

Description

The Model Context Protocol Java SDK is the official Java SDK for Model Context Protocol servers and clients. From version 0.8.0 through 0.12.0 in the io.modelcontextprotocol.sdk:mcp artifact, from 0.13.0 through 0.18.3 and 1.0.0 through 1.1.3 in io.modelcontextprotocol.sdk:mcp-core, and from mcp-core 2.0.0-M1 through 2.0.0, the Servlet-based SSE, Streamable HTTP, and Stateless server transports read an HTTP request body into memory without enforcing a maximum size. An unauthenticated remote client able to reach an affected transport can stream an arbitrarily large POST body, including with chunked transfer encoding, until the Java process exhausts its heap and becomes unavailable. Authentication, Origin or Host validation, or an upstream request-size limit can reject the request before the vulnerable read. The maintained mcp-core lines are fixed in versions 0.18.4, 1.1.4, and 2.0.1.

Affected products

• modelcontextprotocol io.modelcontextprotocol.sdk:mcp: from 0.8.0, < 0.13.0
• modelcontextprotocol io.modelcontextprotocol.sdk:mcp-core: from 0.13.0, < 0.18.4; from 1.0.0, < 1.1.4; from 2.0.0-M1, < 2.0.1

References

• https://github.com/modelcontextprotocol/java-sdk/commit/1499df22c7023aa257223143a5dcf5b1db7ef80d
• https://github.com/modelcontextprotocol/java-sdk/commit/6a41dedaa0625551582d8247e5a4d78eae1131b2
• https://github.com/modelcontextprotocol/java-sdk/commit/8c0fdd1b1f76adba3ce7945d29f73fa2ddc66598
• https://github.com/modelcontextprotocol/java-sdk/commit/9e4d5fa827b6ba69457f5fd93573184789528efa
• https://github.com/modelcontextprotocol/java-sdk/releases/tag/v0.18.4
• https://github.com/modelcontextprotocol/java-sdk/releases/tag/v1.1.4
• https://github.com/modelcontextprotocol/java-sdk/releases/tag/v2.0.1
• https://github.com/modelcontextprotocol/java-sdk/security/advisories/GHSA-4x8c-5vv7-973f

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