CVE-2025-13516
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe SureMail WordPress plugin (versions up to 1.9.0) has an unrestricted file upload vulnerability in its save_file() function. The function copies email attachments to a web-accessible directory (wp-content/uploads/suremails/attachments/) without validating file extensions or content types, using predictable MD5-hash-based filenames. While an .htaccess file attempts to block PHP execution, this protection only works on properly configured Apache servers, leaving nginx, IIS, and Lighttpd installations vulnerable to unauthenticated Remote Code Execution.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm SureMail plugin installation and versionAccess WordPress admin panel, go to Plugins > Installed Plugins, locate SureMail and note the version number. Alternatively, check the plugin's main PHP file header or the version defined in the plugin's main directory (wp-content/plugins/suremail/). Compare the installed version against the affected range (versions up to and including 1.9.0).Affected if SureMail plugin version is 1.9.0 or lower
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Check for the vulnerable upload directoryInspect the file system for the presence of wp-content/uploads/suremails/attachments/ directory. This directory is created when email attachments are saved by the plugin's save_file() function.Affected if The directory wp-content/uploads/suremails/attachments/ exists on the server
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Identify the web server softwareCheck which web server software handles HTTP requests. On Linux/Unix systems, check for nginx, Apache, or Lighttpd processes running (e.g., ps aux | grep -E 'nginx|apache|httpd'). Alternatively, check response headers via curl -I against the site, or review server configuration files in /etc/nginx/, /etc/apache2/, or similar paths.Affected if The web server is nginx, IIS, Lighttpd, or any server other than Apache (since .htaccess protections do not work on these)
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Verify .htaccess protection in attachments directoryCheck if an .htaccess file exists in wp-content/uploads/suremails/attachments/ and review its contents. The protection typically attempts to block PHP execution with directives like 'php_flag engine off' or '<FilesMatch>'.Affected if The server is non-Apache (nginx/IIS/Lighttpd) OR no effective .htaccess protection exists, meaning uploaded scripts could be executed
If SureMail plugin version 1.9.0 or lower is installed, the suremails attachments directory exists, and the web server is nginx, IIS, Lighttpd, or otherwise does not process .htaccess rules, the environment is vulnerable to unauthenticated remote code execution via unrestricted file upload.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpdate to a patched version of the plugin when available, and configure web server-specific rules to deny script execution in the suremails attachments directory for non-Apache servers.
Latest version available from WordPress plugin repository (verify version > 1.9.0)
- Check the WordPress plugin repository or contact the plugin vendor to confirm the latest available version of SureMail
- Upgrade to the latest version available (likely 1.9.1 or higher) which should contain the fix for CVE-2025-13516
- After upgrading, verify that the wp-content/uploads/suremails/attachments/ directory is properly protected or that file upload validation is in place
- If upgrade is not possible immediately, consider disabling email processing features that handle attachments or adding server-level protections (e.g., nginx configuration to block PHP execution in upload directories)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-13516 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-13516 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data