SureMail Plugin up to 1.9.0 on WordPress uploads.php save_file unrestricted upload

Summaryinfo

A vulnerability categorized as critical has been discovered in SureMail Plugin up to 1.9.0 on WordPress. Affected by this issue is the function save_file of the file inc/emails/handler/uploads.php. Such manipulation leads to unrestricted upload. This vulnerability is referenced as CVE-2025-13516. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in SureMail Plugin up to 1.9.0 on WordPress and classified as critical. Affected by this issue is the function save_file of the file inc/emails/handler/uploads.php. The manipulation with an unknown input leads to a unrestricted upload vulnerability. Using CWE to declare the problem leads to CWE-434. The product allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product's environment. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at wordfence.com. This vulnerability is handled as CVE-2025-13516. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 12/02/2025). This vulnerability is assigned to T1608.002 by the MITRE ATT&CK project.

By approaching the search of inurl:inc/emails/handler/uploads.php it is possible to find vulnerable targets with Google Hacking.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• WordPress Plugin

Name

• SureMail Plugin

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9.0

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CPE 2.2info

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