YaySMTP WordPress plugin: Arbitrary file upload via attachment filename extension
Summary
The YaySMTP WordPress plugin up to and including version 2.7.7 does not sufficiently validate file types in its putFile function. Authenticated users with at least Subscriber rights can upload files that may be executable, which can lead to remote code execution on the web server. The only protective .htaccess guard is ineffective on nginx and on Apache configured with AllowOverride None.
Affected
- YaySMTP plugin for WordPress, all versions up to and including 2.7.7
- Default configuration: unaffected according to the CVE record; affected versions as listed above
Fixed in
- Version 2.7.8 (changelog dated 11 October 2026)
Workaround
- No vendor-published workaround.
- Do not rely on the .htaccess guard; it is ineffective on nginx and on Apache with AllowOverride None.
- Deactivate and remove the plugin until it is updated.
- Restrict or disable public user registration and review existing Subscriber accounts.
- Check upload directories for unexpected script files and make sure PHP cannot execute there at web-server level.
Exploitation
- Authentication required: Subscriber-level account or higher.
- In the wild: not found in the research.
- CISA KEV: not listed according to a third-party tracker; not verified directly.
- EPSS: 0.00575 according to one aggregator; unknown in another tracker.
- Public proof of concept: none found, but the search was limited.
Our recommendation
- Update YaySMTP to version 2.7.8 or later on all WordPress sites.
- If an update is not possible, deactivate the plugin.
- Review the site for unexpected files, especially in upload directories, and for unknown Subscriber accounts.
- Restrict open user registration and monitor for unusual uploads or new accounts.
- Treat sites with YaySMTP 2.7.7 or older as high priority.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- WordPress plugin trac: EmailLogAttachments.php (2.7.7) plugins.trac.wordpress.org
- WordPress plugin trac changeset 3739875 plugins.trac.wordpress.org
- Wordfence threat intelligence entry www.wordfence.com
- WordPress.org YaySMTP plugin page wordpress.org
- CVE description mirror (threatint) cve.threatint.com
- Strix CVE entry www.strix.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 16:05.
Original description (NVD)
The YaySMTP – WP Mail SMTP with Email Logs, Tracking & Reports plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 2.7.7 via the putFile function. This is due to insufficient file type validation in the putFile function, as sanitize_file_name() does not strip executable extensions and no allow-list, MIME check, or safe-extension rename is applied. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. The only server-side guard is a .htaccess file containing 'Require all denied' written by writeGuards(), which is silently ignored by nginx and by Apache configured with AllowOverride None, meaning RCE is fully achievable on those server configurations.
NVD references (8)
- https://plugins.trac.wordpress.org/browser/yaysmtp/tags/2.7.7/includes/Helper/EmailLogAttachments.php#L106
- https://plugins.trac.wordpress.org/browser/yaysmtp/tags/2.7.7/includes/Helper/EmailLogAttachments.php#L178
- https://plugins.trac.wordpress.org/browser/yaysmtp/tags/2.7.7/includes/Helper/EmailLogAttachments.php#L542
- https://plugins.trac.wordpress.org/browser/yaysmtp/tags/2.7.7/includes/Helper/EmailLogAttachments.php#L549
- https://plugins.trac.wordpress.org/browser/yaysmtp/tags/2.7.7/includes/Helper/Utils.php#L814
- https://plugins.trac.wordpress.org/browser/yaysmtp/tags/2.7.7/includes/PluginCore.php#L37
- https://plugins.trac.wordpress.org/changeset/3739875/yaysmtp/trunk/includes/Helper/EmailLogAttachments.php
- https://www.wordfence.com/threat-intel/vulnerabilities/id/4abbf148-4648-440c-8a82-cf68bf051fbe?source=cve
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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