CyberRota Analysis
AI-GeneratedThe MCP PHP SDK versions 0.5.0 to 0.7.0 are vulnerable due to an unbounded memory allocation in the HTTP client transport, which can be exploited by a malicious server to exhaust the client's memory resources. This can lead to a denial of service, causing fatal allocation errors or triggering an out-of-memory kill on the client process. Organizations using this SDK, particularly those connecting to untrusted server endpoints, should prioritize upgrading to version 0.7.1 to mitigate this risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
Note: these links are listed for security research and verification purposes only.
Original NVD Description
The MCP PHP SDK (Composer package mcp/sdk) is the official Model Context Protocol SDK for PHP. In versions 0.5.0 through 0.7.0, the HTTP client transport reads a Server-Sent Events response stream incrementally and appends each chunk to an in-memory buffer with no upper bound. The buffer is only flushed when an SSE event delimiter, a double newline, is found, so a remote MCP server that streams response bytes without ever sending the delimiter causes the buffer to grow without limit. A malicious, compromised, or man-in-the-middle-controlled server that the client connects to over the HTTP transport can exploit this to exhaust the client process's memory, triggering a fatal allocation error or OS out-of-memory kill and denying service to the MCP client. The issue affects any client using HttpTransport against an untrusted server endpoint and does not require authentication or user interaction beyond initiating the connection. This issue is fixed in version 0.7.1.