Huimeicloud hm_editor Server-Side Request Forgery Vulnerability (CVE-2026-5346)

A server-side request forgery (SSRF) vulnerability has been identified in huimeicloud hm_editor, specifically affecting versions up to 2.2.3. The vulnerability resides within the client.get function in the src/mcp-server.js file, which is part of the image-to-base64 endpoint. By manipulating the url argument, a remote attacker can potentially force the server to make requests to unintended locations, including internal resources. This vulnerability, identified as CVE-2026-5346, has a CVSS v3.1 score of 7.3 and is remotely exploitable. Public exploits are available. The vendor was notified but has not responded.

Attack Chain

1. The attacker identifies an instance of huimeicloud hm_editor running version 2.2.3 or earlier.
2. The attacker crafts a malicious URL containing a payload designed to exploit the SSRF vulnerability in the image-to-base64 endpoint.
3. The attacker sends a request to the vulnerable endpoint (src/mcp-server.js) with the crafted url parameter.
4. The client.get function processes the attacker-controlled url argument without proper validation.
5. The server-side application initiates an HTTP request based on the manipulated URL, potentially targeting internal resources or external services.
6. The server receives the response from the targeted resource.
7. The server may process and return the data obtained from the targeted resource to the attacker or use it internally.
8. The attacker gains unauthorized access to internal information or leverages the server as a proxy for further attacks.

Impact

Successful exploitation of this SSRF vulnerability (CVE-2026-5346) can lead to unauthorized access to internal resources, sensitive data exposure, and the ability to use the vulnerable server as a proxy for further attacks. The impact includes potential compromise of internal systems, circumvention of security controls, and data breaches. The affected component is the image-to-base64 endpoint, which may be used to process user-supplied images.

Recommendation

• Apply input validation and sanitization to the url argument passed to the client.get function within the src/mcp-server.js file to prevent SSRF attacks, mitigating CVE-2026-5346.
• Monitor web server logs for suspicious requests targeting the image-to-base64 endpoint (src/mcp-server.js) with unusual url parameters, using the provided Sigma rule to identify exploitation attempts.
• Implement network segmentation to limit the impact of successful SSRF attacks by restricting access to internal resources from the vulnerable server.
• Deploy the Sigma rule to detect attempts to exploit CVE-2026-5346, focusing on unusual URLs being passed to the image-to-base64 endpoint.