CVE-2026-77339

Medium

Description

Process Compose is a scheduler and orchestrator for non-containerized applications. Prior to 1.120.0, the MCP SSE listener in src/mcp/server.go accepts browser-origin requests to /sse and the returned message endpoint without validating the Host header, validating the Origin header, or authenticating the caller. When MCP SSE is enabled, a malicious website can use DNS rebinding to reach the loopback listener and issue MCP requests. If expose_control_tools is enabled, the attacker can enumerate process state, read or search logs, truncate logs, and start, stop, restart, or scale local processes; configured user-defined tools can expose additional commands and output. The Gin REST API token middleware does not protect this separately started MCP listener. This issue is fixed in version 1.120.0.

SeverityMedium
CVSS5.1
Exploit probability—
ProductGithub.com/f1bonacc1/process-compose
PublishedSep 18, 2026
First seenSep 18, 2026

How to fix

Update
  • github.com/f1bonacc1/process-compose1.120.0 or later

Affected products

ProductAffected versionsFixed in
github.com/f1bonacc1/process-composeGov < 1.120.01.120.0

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