CVE-2026-39313
Received Received - Intake
Unrestricted Memory Allocation in mcp-framework Causes DoS

Publication date: 2026-04-16

Last updated on: 2026-04-16

Assigner: GitHub, Inc.

Description
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.
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Meta Information
Published
2026-04-16
Last Modified
2026-04-16
Generated
2026-06-16
AI Q&A
2026-04-17
EPSS Evaluated
2026-06-15
NVD
CVE-2026-39313
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
quantgeekdev mcp-framework to 0.2.22 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
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Executive Summary

The vulnerability exists in the mcp-framework versions 0.2.21 and below, specifically in the readRequestBody() function of the HTTP transport. This function concatenates incoming request body chunks into a string without enforcing any size limit, despite the presence of a maxMessageSize configuration value that is never applied. As a result, a remote unauthenticated attacker can send a single large POST request to the /mcp endpoint, causing the server to exhaust its memory and crash.

Impact Analysis

This vulnerability can lead to a denial of service (DoS) condition on any mcp-framework HTTP server running vulnerable versions. An attacker can remotely crash the server by sending a large POST request, causing memory exhaustion. This disrupts the availability of the service, potentially leading to downtime and loss of access for legitimate users.

Mitigation Strategies

To mitigate this vulnerability, upgrade the mcp-framework to version 0.2.22 or later, where the issue has been fixed.

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