Description

In Oraios AI Serena before 1.0.0, the listen address of the MCP server in HTTP mode is 0.0.0.0. NOTE: the Supplier observed that 0.0.0.0 was a "potential security hazard" but the Serena documentation, at the time of the issue report proposing 127.0.0.1 instead of 0.0.0.0, recommended "use a sandboxed environment for running Serena."

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "2.9",
  "pubDate": "2026-09-14T03:16:36.893Z",
  "pubdate": "2026-09-14T03:16:36.893Z",
  "executiveSummary": "Oraios AI Serena versions prior to 1.0.0 exhibit an insecure default network configuration where the Model Context Protocol (MCP) server, operating in HTTP mode, binds to the 0.0.0.0 network interface.\nThis configuration results in the server listening on all available network interfaces rather than being restricted to the local loopback (127.0.0.1).\nThe primary risk implication is the unintended exposure of the MCP server to external network segments, potentially allowing unauthorized actors to interact with the service.\nWhile the supplier recommended the use of a sandboxed environment to mitigate risks, the lack of secure binding defaults increases the attack surface for deployments not explicitly hardened.\nAn attacker with network visibility can reach the service directly, bypassing internal protections intended for local-only access.\nThis vulnerability is classified as an improper restriction of network service exposure, which could lead to unauthorized access, information disclosure, or further compromise of the Serena integration environment.",
  "technicalDetails": "The vulnerability originates from the default listen address configuration within the Oraios AI Serena MCP server component.\nWhen initialized in HTTP mode, the server defaults to binding to 0.0.0.0, which instructs the underlying network stack to accept incoming connection requests on any interface assigned to the host system.\nIn contrast, a secure implementation should default to 127.0.0.1 (localhost) to restrict access exclusively to processes executing on the same host, thereby adhering to the principle of least privilege regarding network exposure.\nThe attack flow begins with an attacker performing network reconnaissance to identify open ports on a target host. Upon identifying the port utilized by the Serena MCP server, an attacker—even those situated on the same local area network (LAN) or a routable segment—can initiate an HTTP connection to the service.\nBecause the server is bound to 0.0.0.0, it processes the request as legitimate traffic. If the MCP server lacks additional network-layer authentication or if the implementation assumes inherent trust based on local proximity, the attacker can interact with the server's API endpoints.\nThis exposure allows unauthorized parties to leverage the capabilities of the MCP server, potentially leading to unauthorized model context injection, data exfiltration, or interactions with integrated LLM tools that the Serena instance manages.\nThe technical root cause is the deviation from secure-by-default network programming practices in the service initialization routine. By failing to restrict the listen socket to the loopback interface, the service assumes a level of network isolation that is not provided by the default configuration.\nExploitation does not require authentication to the Serena application itself, as the entry point is the network socket exposed by the service process. If the service relies on the assumption that only local users can reach the MCP server, the exposure on 0.0.0.0 effectively nullifies this security boundary, granting remote, unauthenticated access to the underlying MCP functionality.\nThe post-exploitation impact is contingent upon the specific tools and capabilities enabled within the Serena configuration, but generally includes the potential for command execution within the context of the MCP integration or the unauthorized retrieval of sensitive session context or application data."
}