CVE-2026-39313CWE-770

MCP-Framework: Unbounded memory allocation in readRequestBody allows denial of service via HTTP transport

High · published April 16, 2026

CVSS v4.0
8.7
EPSS
1%
Percentile
46.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS
0.00566 · 46.2th percentile
Weakness
CWE-770 · Allocation of Resources Without Limits or Throttling
Published
2026-04-16T21:24Z
EPSS history
Timeline
  • 16 APR 21:24Z
    MCP-Framework: Unbounded memory allocation in readRequestBody allows denial of service via HTTP transport
    cvelistv5