CVE-2025-49596 Scanner

MCP Inspector is a developer tool used primarily by software developers and engineers for testing and debugging Model Context Protocol (MCP) servers. It serves as an intermediary that allows developers to interact with and monitor MCP servers through both graphical and command-line interfaces. Developers use MCP Inspector to ensure their MCP servers are running correctly, identify problems, optimize performance, and test new features before releasing them to a live environment. It is frequently employed in development and staging environments for continuous integration and deployment processes. MCP Inspector is designed for professionals looking to streamline their workflow when working with complex server environments. The tool is widely used due to its efficiency in debugging and interaction with MCP protocol servers.

Remote Code Execution (RCE) is a critical security vulnerability that allows attackers to execute arbitrary code on a vulnerable system. In the case of MCP Inspector, versions below 0.14.0 are susceptible to RCE due to inadequate authentication protocols between the client and the proxy server. This vulnerability arises from the lack of proper security mechanisms that prevent unauthorized execution of MCP commands over standard input/output. The risk associated with this vulnerability is high given the potential for attackers to gain complete control over the server. The lack of authentication makes it easy for an attacker to inject malicious commands, leading to data breaches, system compromises, and possible denial of service. Patching this vulnerability is critical to maintaining system integrity and preventing unauthorized access.

The vulnerability arises from improper validation of the authenticity of requests made to the MCP Inspector. The application lacks mechanisms to authenticate users, particularly for requests sent via standard input-output. Attackers can exploit this flaw by crafting requests that trigger the execution of arbitrary MCP commands. The endpoint `{{BaseURL}}/sse?transportType=stdio&command=echo&args[]=hello-from-browser` is used as an entry point for potential attacks, leveraging the RCE vulnerability. The templated script identifies the vulnerable parameter as the endpoint for session handling, which, if exploited, can lead to potential system compromise. The verification process involves ensuring that the system responds inappropriately to crafted test conditions, indicating the presence of the RCE vulnerability.

Exploiting the RCE vulnerability can have dire consequences, including unauthorized access to system resources, information disclosure, and destructive system manipulation. The attacker can launch arbitrary commands, potentially leading to data corruption or deletion, unauthorized data exfiltration, and manipulation or shutdown of critical services. Furthermore, the exploitation could be used to pivot further attacks onto internal network segments, affecting the broader system security posture. Additionally, this vulnerability might allow privileges escalation, enabling the attacker to gain higher access levels and perform more dangerous actions. Overall, exploitation of this vulnerability can severely affect an organization's operational capabilities, reputation, and data security.

REFERENCES

• https://nvd.nist.gov/vuln/detail/CVE-2025-49596
• https://github.com/modelcontextprotocol/inspector
• https://github.com/modelcontextprotocol/inspector/commit/50df0e1ec488f3983740b4d28d2a968f12eb8979
• https://github.com/modelcontextprotocol/inspector/security/advisories/GHSA-7f8r-222p-6f5g
• https://www.oligo.security/blog/critical-rce-vulnerability-in-anthropic-mcp-inspector-cve-2025-49596