AIKIDO-2026-523598
mcp/sdk is vulnerable to Uncontrolled Resource Consumption
75
High Risk
This Affects:
mcp/sdkTL;DR
The client HTTP transport reads a Server-Sent-Events response stream incrementally and appends each chunk to a buffer that is only flushed once the \n\n event delimiter arrives. A connected MCP server, or any party able to control that server's response body, can stream bytes that never contain the delimiter so the buffer grows without bound until the client process exhausts its memory limit. This lets an untrusted peer crash a connected client. The fix caps the buffered bytes, aborts the stream when the cap is exceeded, and fails the pending request immediately.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and your application uses the client HTTP transport to connect to an MCP server whose Server-Sent-Events response stream can be influenced by untrusted input.
Background info
mcp/sdk is vulnerable to Uncontrolled Resource Consumption in versions 0.5.0 - 0.7.0.
How to fix this
Upgrade the mcp/sdk library to the patch version.
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SOC 2Compliant
ISO 27001Compliant