F1bonacc1 Process Compose up to 1.119.x MCP SSE Listener src/mcp/server.go dns rebinding

Summaryinfo

A vulnerability categorized as critical has been discovered in F1bonacc1 Process Compose up to 1.119.x. This affects an unknown function of the file src/mcp/server.go of the component MCP SSE Listener. The manipulation results in dns rebinding. This vulnerability is identified as CVE-2026-77339. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in F1bonacc1 Process Compose up to 1.119.x. Affected is an unknown functionality of the file src/mcp/server.go of the component MCP SSE Listener. The manipulation with an unknown input leads to a dns rebinding vulnerability. CWE is classifying the issue as CWE-350. The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-77339 since 08/20/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1583.002 by the MITRE ATT&CK project.

Upgrading to version 1.120.0 eliminates this vulnerability.

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Productinfo

Vendor

• F1bonacc1

Name

• Process Compose

Version

• 1.119

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CPE 2.2info

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