Gemini CLI 0.59.0 blocks server-side request forgery in MCP OAuth

What changed

Version 0.59.0 adds SSRF protection to MCP OAuth metadata discovery, dynamic client registration and token exchange. Remote OAuth endpoints must use HTTPS (plain HTTP is allowed only for a local loopback server), and endpoints pointing at private, loopback, link-local or cloud-metadata addresses such as 169.254.169.254 are rejected. DNS is resolved before each request to defeat rebinding.

Who it affects

Gemini CLI users who connect to remote MCP servers that use OAuth, especially on cloud VMs.

What to do

Upgrade to 0.59.0 or later; if an internal MCP server stops authenticating, make sure its OAuth endpoints use HTTPS.

Source: https://github.com/google-gemini/gemini-cli/releases/tag/v0.59.0