CVE-2026-86122 in Rowboat
Summary
by MITRE • 09/05/2026
Rowboat through 0.9.1 fails to validate custom MCP server and webhook URLs, allowing authenticated users to configure arbitrary destinations. Attackers can point these URLs at internal services and cloud metadata endpoints to perform server-side request forgery and enumerate internal network topology.
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Analysis
by VulDB Data Team • 09/05/2026
The vulnerability in Rowboat versions prior to 0.9.1 represents a critical failure in input validation for user-supplied configuration data, specifically concerning custom Model Context Protocol (MCP) servers and webhook destinations. This flaw allows authenticated users to inject arbitrary Uniform Resource Locators into the application's configuration parameters without sufficient sanitization or domain restriction checks. By failing to validate that these URLs point only to expected external services, the software inadvertently creates a vector for Server-Side Request Forgery attacks. An attacker who has obtained valid credentials can manipulate these settings to force the Rowboat server to initiate HTTP requests on their behalf toward internal infrastructure components that are otherwise inaccessible from the public internet or restricted by network segmentation policies.
The operational impact of this vulnerability is severe, as it effectively bypasses perimeter security controls and allows an authenticated user to pivot into the internal network topology. Attackers can direct these forged requests toward cloud metadata endpoints, such as those found in AWS EC2 Instance Metadata Service (IMDS) or Azure Managed Identity endpoints, which often contain sensitive authentication tokens and configuration details. Furthermore, by targeting internal services like database servers, message queues, or administrative interfaces, the attacker can perform network enumeration, probe for open ports, and potentially interact with backend systems to extract data or trigger unintended actions. This capability transforms a standard authenticated user account into a powerful tool for lateral movement and deep reconnaissance within the organization's environment.
From a classification perspective, this vulnerability aligns closely with CWE-20 Improper Input Validation, as the application fails to verify that the input conforms to expected constraints regarding scheme, host, or port. It also maps directly to MITRE ATT&CK technique T1598 Phishing for Information within Cloud Environments and potentially T1046 Network Service Discovery when used for enumeration purposes. The core issue lies in the lack of a strict allowlist mechanism for URL destinations, relying instead on insufficient checks that can be easily circumvented by an attacker familiar with internal network structures or cloud metadata service patterns.
To mitigate this risk, organizations running Rowboat versions up to 0.9.1 should immediately upgrade to version 0.9.2 or later where the input validation logic has been corrected. In cases where upgrading is not immediately feasible, administrators can implement a reverse proxy configuration that restricts outbound connections from the application server to only known and approved external domains, effectively blocking requests to internal IP ranges and cloud metadata endpoints. Additionally, enforcing strict network segmentation policies ensures that even if such forged requests are made, they cannot reach sensitive backend services or metadata stores. Regular auditing of user-configured settings and implementing principle of least privilege for API access can further reduce the attack surface associated with this type of server-side request forgery vulnerability.