Email Customizer for WooCommerce (Pro): Remote Code Execution in send_test_mail()
Summary
The Email Customizer for WooCommerce (Pro) plugin for WordPress, versions up to and including 3.9.5, does not sufficiently check authorization and input in the send_test_mail() function. An authenticated attacker with at least subscriber-level access can write user-controlled PHP code into executable files in the uploads directory and run arbitrary code on the server. This can lead to full compromise of the website.
Affected
- Email Customizer for WooCommerce (Pro) WordPress plugin, versions 0 to and including 3.9.5
Fixed in
- Version 3.9.6 is listed as current on the ThemeHigh product page, but the fix for this CVE is not confirmed.
- The ThemeHigh changelog excerpt for 3.9.6 only mentions WooCommerce 11.1 and WordPress 7.1 compatibility.
- Verify the fixed version before rollout.
Workaround
- No vendor workaround published.
- If no fix can be applied, deactivate the Pro plugin, as the test mail feature is the affected path.
- Restrict or disable open user registration.
- Check the uploads directory for unexpected PHP files.
Exploitation
- CISA SSVC: exploitation none, automatable yes.
- Not listed in CISA KEV.
- EPSS about 0.5%.
- No public proof of concept found in the search performed; this is not an exhaustive check.
- No confirmed in-the-wild exploitation known.
Our recommendation
- Verify the fixed version in the ThemeHigh changelog and update the plugin promptly.
- If patching is not possible, deactivate the Pro plugin.
- Restrict user registration on sites that run the plugin.
- Search the uploads directory for PHP files and review recent file changes; treat any finding as a possible compromise.
- Prioritise public WooCommerce shops with open registration.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- ThemeHigh changelog www.themehigh.com
- Wordfence threat intelligence record www.wordfence.com
- ThemeHigh product page www.themehigh.com
- CVE-2026-81534 Vulnrichment (CISA SSVC, EPSS) vulners.com
- CVE-2026-81534 CVE record data (OpenCVE) app.opencve.io
- CVE-2026-81534 analysis (Strix, secondary) 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, 16:35.
Original description (NVD)
The Email Customizer for WooCommerce (Pro) plugin for WordPress is vulnerable to Remote Code Execution in versions up to, and including, 3.9.5. This is due to insufficient authorization and input sanitization in the send_test_mail() function, which allows user-controlled PHP code to be written to executable files in the uploads directory. This makes it possible for authenticated attackers, with subscriber-level access and above, to execute arbitrary PHP code on the server, leading to full site compromise.
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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