The vulnerability CVE-2024-9417 affects the Hash Form – Drag & Drop Form Builder plugin for WordPress, present in all versions up to and including 1.1.9. It stems from a misconfiguration in the 'handleUpload' function, which inadequately validates file types during upload. Specifically, the plugin maintains two arrays: 'allowedExtensions' and 'unallowed_extensions', but the validation logic fails to properly exclude files that do not appear in either list. This gap allows unauthenticated attackers to upload files with extensions that are neither explicitly allowed nor disallowed, including potentially dangerous file types capable of executing cross-site scripting (XSS) payloads. The vulnerability does not require authentication, increasing its risk, but does require user interaction to upload files. The impact includes the possibility of executing malicious scripts in the context of the vulnerable website, which can lead to theft of user credentials, session hijacking, or defacement. The vulnerability has a CVSS v3.1 base score of 6.1 (medium severity), reflecting network attack vector, low attack complexity, no privileges required, but user interaction needed, and partial confidentiality and integrity impact. No patches or official fixes have been published at the time of disclosure, and no known exploits are reported in the wild. The vulnerability is categorized under CWE-434 (Unrestricted Upload of File with Dangerous Type).

Organizations using the Hash Form – Drag & Drop Form Builder plugin are at risk of unauthorized file uploads that can lead to cross-site scripting attacks. This can compromise the confidentiality of user data by stealing cookies or session tokens, and integrity by enabling attackers to inject malicious scripts or modify site content. Although availability is not directly impacted, successful exploitation can undermine user trust and lead to reputational damage. Since the vulnerability requires no authentication, attackers can exploit it remotely without credentials, increasing the attack surface. The scope includes any WordPress site using the affected plugin version, which may be widespread given WordPress's market share. The lack of known exploits suggests limited active exploitation currently, but the vulnerability is straightforward to exploit, making it a likely target for attackers once weaponized. Organizations with public-facing WordPress sites that accept user uploads via this plugin are particularly vulnerable.

1. Immediately disable file upload functionality in the Hash Form plugin if it is not essential to your site's operation. 2. Implement strict server-side validation of uploaded files, including MIME type checks, file extension whitelisting, and content inspection to block executable or script files. 3. Use a web application firewall (WAF) to detect and block suspicious upload attempts targeting this vulnerability. 4. Monitor upload directories for unexpected or suspicious files and remove them promptly. 5. Restrict permissions on upload directories to prevent execution of uploaded files. 6. Keep WordPress core, plugins, and themes updated; monitor the vendor's site for official patches or updates addressing this vulnerability. 7. Educate site administrators about the risks of accepting file uploads from unauthenticated users and enforce strict upload policies. 8. Consider isolating the upload functionality in a sandboxed environment to limit potential damage from malicious files.