CVE-2020-36565 is a medium-severity vulnerability classified under CWE-22, which pertains to improper limitation of a pathname to a restricted directory, commonly known as a path traversal vulnerability. This specific issue affects the static file handler component of the github.com/labstack/echo/v4 web framework, a popular Go-based HTTP server framework. The vulnerability arises due to improper sanitization of user-supplied input on Windows operating systems. When serving static files, the handler fails to adequately restrict pathname inputs, allowing an attacker to craft specially designed requests that traverse directories outside the intended static file root directory. This enables unauthorized reading of arbitrary files on the server, limited only by the permissions of the server process. The vulnerability does not require authentication or user interaction and can be exploited remotely over the network. The CVSS 3.1 base score is 5.3 (medium), reflecting that the attack vector is network-based with low complexity and no privileges or user interaction required. The impact is limited to confidentiality, as the attacker can read files but cannot modify or delete them, nor cause denial of service. The vulnerability is specific to Windows environments due to the way path sanitization is handled on that platform. There are no known exploits in the wild at this time, and no official patches or mitigation links are provided in the source information. The affected version is indicated as "0," which likely means all versions prior to a fix or a specific early release version. Overall, this vulnerability allows an attacker to bypass directory restrictions in the static file handler of the Echo framework on Windows, potentially exposing sensitive files such as configuration files, credentials, or other data accessible by the server process.

For European organizations using the github.com/labstack/echo/v4 framework on Windows servers, this vulnerability poses a risk of unauthorized disclosure of sensitive information. The ability to read arbitrary files can lead to exposure of configuration files, environment variables, source code, or credentials, which could facilitate further attacks such as privilege escalation or lateral movement. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and government, could face compliance risks if sensitive personal or confidential data is exposed. The impact is primarily on confidentiality, with no direct impact on integrity or availability. However, the information gained could be leveraged in multi-stage attacks. Since the vulnerability is specific to Windows deployments of the Echo framework, organizations running Linux-based servers are not affected. The lack of known exploits reduces immediate risk, but the ease of exploitation and network accessibility mean that attackers could develop exploits quickly once awareness increases. European organizations with public-facing web applications using Echo on Windows should consider this vulnerability a moderate threat that requires timely remediation to prevent data leakage.

1. Upgrade to a fixed version of github.com/labstack/echo/v4 where the path traversal vulnerability has been addressed. If no official patch is available, monitor the vendor repository for updates and apply them promptly. 2. Implement strict input validation and sanitization on all user-supplied path parameters, ensuring that directory traversal characters (e.g., '..', '\') are properly handled or rejected. 3. Configure the web server and application to run with the least privilege necessary, restricting file system permissions so that the server process cannot read sensitive files outside the intended directories. 4. Employ application-layer access controls to restrict access to sensitive files and directories, possibly using allowlists for static content. 5. Use Web Application Firewalls (WAFs) with rules designed to detect and block path traversal attempts targeting the Echo framework. 6. Conduct security testing and code reviews focusing on file handling and input sanitization, especially on Windows deployments. 7. Monitor logs for suspicious requests containing directory traversal patterns and respond to potential exploitation attempts. 8. Where possible, consider deploying the Echo framework on Linux-based servers, which are not affected by this specific vulnerability, as a temporary mitigation.