# YayMail – WooCommerce Email Customizer <= 4.4.6 - Authenticated (Shop Manager+) PHP Object Injection via Backup State Import

- **ID:** WPSEC-2026-0868
- **Plugin:** YayMail – WooCommerce Email Customizer (`yaymail`), https://wordpress.org/plugins/yaymail/
- **Affected versions:** from 4.2.0 before 4.4.7
- **Fixed in:** 4.4.7 (Update to 4.4.7 or later.)
- **Severity:** Medium 6.6 (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H)
- **Weakness:** CWE-502
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-10-13)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/yaymail
- **Fix released:** 2026-10-13
- **Published:** 2026-10-14
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0868/

## Description

The YayMail – WooCommerce Email Customizer plugin for WordPress is vulnerable to PHP Object Injection via the backup state import (yaymail_import_state AJAX action) in all versions up to, and including, 4.4.6. This is due to deserialization of untrusted input. Imported postmeta and option values were unserialized with allowed_classes set to false, and only a top-level object was rejected. Objects nested inside arrays survived as incomplete objects. When the values were saved with add_post_meta() and update_option(), these incomplete objects were serialized again under their original class names, and WordPress later instantiates them with maybe_unserialize() when it reads the values back. This makes it possible for authenticated attackers with Shop Manager-level access and above to inject a PHP object through a crafted backup ZIP file. No known POP chain is present in the vulnerable plugin itself. If a POP chain is present through another plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

## References

- https://wpsec.com/vuln/WPSEC-2026-0868/
- https://plugins.svn.wordpress.org/yaymail/tags/4.4.7/
- https://wordpress.org/plugins/yaymail/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0868/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.