CVE Catalog

CVE-2026-77339

MediumCVSS 5.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.26%

15th percentile - higher than 15% of all known CVEs

Summary

Process Compose before version 1.120.0 has a vulnerability in the MCP SSE listener that accepts browser-origin requests without validating Host/Origin headers or authenticating the caller. A malicious website can use DNS rebinding to reach the loopback listener and issue MCP requests, potentially allowing process enumeration, log access, and process control if expose_control_tools is enabled. Fixed in version 1.120.0.

Risk Assessment

An attacker could gain control over processes and logs, leading to confidentiality, integrity, and availability breaches.

Recommendation

Update Process Compose to version 1.120.0 or later. If not possible, disable MCP SSE or expose_control_tools.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS