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Vulnerability · Published Oct 14, 2026 · Assigned by GitHub_M

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

High 7.5

In plain English

A high-severity resource allocation without limits in io.modelcontextprotocol.sdk:mcp from modelcontextprotocol. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.6%top 50.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 (as reported)

VendorProductVersions
modelcontextprotocol io.modelcontextprotocol.sdk:mcp >= 0.8.0, < 0.13.0
modelcontextprotocol io.modelcontextprotocol.sdk:mcp-core >= 0.13.0, < 0.18.4>= 1.0.0, < 1.1.4>= 2.0.0-M1, < 2.0.1

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References