functype-mcp-server: MCP `set_functype_version` Package Alias RCE

Published September 9, 2026 CVE-2026-59176

functype-mcp-server can let an attacker run their own code inside the MCP server. That code can read secrets, change files, or crash the service.

Severity
HighCVSS 7.8
Fix
Fixed in 1.4.4Fix recorded yesterday
Affected versions
1.4.3 or older
Affects
functype-mcp-server

How it works

  • The server accepts any version text through its set_functype_version tool.
  • It passes that text to pnpm, which can install an unintended local or remote package.
  • The server then loads code from that package, allowing attacker-controlled JavaScript to run with the server's permissions.

What to do

Run npm list functype-mcp-server in each environment using the package. Versions 1.4.3 or earlier are affected; version 1.4.4 or later is outside the affected range.

Run this in the application environment you want to check:

npm list functype-mcp-server

Upgrade functype-mcp-server to version 1.4.4 or later. See the security advisory for the fixed release.

Technical details

CVE-2026-59176 is rated High with a CVSS score of 7.8. The vulnerable MCP tool passes an unrestricted version string to pnpm, then dynamically loads the installed package inside the server process.

References

View Original Source