CVE Catalog

CVE-2026-108395

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.61%

48th percentile - higher than 48% of all known CVEs

Summary

The Model Context Protocol Java SDK, 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 mcp-core, and from mcp-core 2.0.0-M1 through 2.0.0, reads HTTP request bodies into memory without enforcing a maximum size in Servlet-based SSE, Streamable HTTP, and Stateless server transports. An unauthenticated remote client can stream an arbitrarily large POST body, including chunked transfer encoding, until the Java process exhausts its heap and becomes unavailable.

Risk Assessment

An attacker can exhaust memory and take down the MCP service, causing denial of service for all clients. The risk applies to any deployment exposing an affected server transport without a request-size limit.

Recommendation

Upgrade mcp-core to version 0.18.4, 1.1.4, or 2.0.1 (or later). Additionally, enforce a request-size limit at the proxy layer and require authentication and Origin/Host validation.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS