FastMCP

v4.0.2 Security

This release includes 1 security fix for security teams reviewing exposed deployments.

Published 1mo MCP Developer Tools

✓ No known CVEs patched

This release patches 1 known CVE

Topics

mcp sse

Affected surfaces

auth

Summary

AI summary

Fixed OAuthProxy credential leak and improved redirect_uri validation.

Type	Severity	Summary	CVE
Bugfix	Medium	Fixes OAuthProxy credential leak and redirect_uri validation. Fixes OAuthProxy credential leak and redirect_uri validation. Source: llm_adapter@2026-06-06 Confidence: low	—

Full changelog

auth: fix OAuthProxy credential leak and redirect_uri validation (#262) (43f5f2e)

Weekly OSS security release digest.

The CVE patches and breaking changes that affected production tools this week. One email, every Sunday.

No spam, unsubscribe anytime.

Share this release

Track FastMCP

Get notified when new releases ship.

About FastMCP

A high-level framework for building MCP servers in TypeScript