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Unrestricted Upload of File with Dangerous Type

CVE-2025-13516

High
8.1/10

Summary

The SureMail – SMTP and Email Logs Plugin for WordPress is vulnerable to Unrestricted Upload of File with Dangerous Type in versions up to and including 1.9.0. This is due to the plugin's save_file() function in inc/emails/handler/uploads.php which duplicates all email attachments to a web-accessible directory (wp-content/uploads/suremails/attachments/) without validating file extensions or content types. Files are saved with predictable names derived from MD5 hashes of their content. While the plugin attempts to protect this directory with an Apache .htaccess file to disable PHP execution, this protection is ineffective on nginx, IIS, and Lighttpd servers, or on misconfigured Apache installations. This makes it possible for unauthenticated attackers to achieve Remote Code Execution by uploading malicious PHP files through any public form that emails attachments, calculating the predictable filename, and directly accessing the file to execute arbitrary code granted they are exploiting a site running on an affected web server configuration.

  • HIGH
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-434 - Unrestricted Upload of File with dangerous type

'Unrestricted file upload with dangerous type' attacks involve an attacker uploading or transferring files of dangerous types to the server. The severity of such an attack depends upon the execution mechanism and the storage location of the uploaded file. Thus, it may range from simple defacement to arbitrary file execution, and complete system takeover.

References

Advisory Timeline

  • Published