CVE Catalog

CVE-2026-39313

High
Published: Translated: NVD NIST

Summary

mcp-framework versions 0.2.21 and below have a vulnerability in the readRequestBody() function in the HTTP transport that concatenates request body chunks into a string with no size limit. Although a maxMessageSize configuration value exists, it is never enforced. A remote unauthenticated attacker can crash any mcp-framework HTTP server by sending a single large POST request to /mcp, causing memory exhaustion and DoS.

Risk Assessment

The risk includes a DoS attack on MCP servers, potentially disrupting services.

Recommendation

Upgrade to version 0.2.22 which contains the fix.

Related vulnerabilities

Original NVD description (English source)

mcp-framework is a framework for building Model Context Protocol (MCP) servers. In versions 0.2.21 and below, the readRequestBody() function in the HTTP transport concatenates request body chunks into a string with no size limit. Although a maxMessageSize configuration value exists, it is never enforced in readRequestBody(). A remote unauthenticated attacker can crash any mcp-framework HTTP server by sending a single large POST request to /mcp, causing memory exhaustion and denial of service. This issue has been fixed in version 0.2.22.

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