# MainWP Child – Securely Connects to the MainWP Dashboard to Manage Multiple Sites <= 6.2.1 - Unauthenticated PHP Object Injection via Clone/Restore Database Values

- **ID:** WPSEC-2026-0460
- **Plugin:** MainWP Child – Securely Connects to the MainWP Dashboard to Manage Multiple Sites (`mainwp-child`), https://wordpress.org/plugins/mainwp-child/
- **Affected versions:** all versions before 6.2.2
- **Fixed in:** 6.2.2 (Update to 6.2.2 or later.)
- **Severity:** High 7.5 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H)
- **Weakness:** CWE-502
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-10-06)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/mainwp-child
- **Fix released:** 2026-10-05
- **Published:** 2026-10-06
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0460/

## Description

The MainWP Child plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 6.2.1 via deserialization of untrusted input in the recursive_unserialize_replace function. When a site is cloned or restored, every serialized-looking value in the restored database is passed to unserialize() without restricting allowed classes. This makes it possible for unauthenticated attackers to place a serialized PHP object in a stored value they can write, such as a comment, which is instantiated when an administrator later clones or restores a backup containing that value. Impact depends on a POP chain being available through the site's installed plugins or themes, which could allow file deletion, sensitive data retrieval, or code execution.

## References

- https://wpsec.com/vuln/WPSEC-2026-0460/
- https://plugins.svn.wordpress.org/mainwp-child/tags/6.2.2/
- https://wordpress.org/plugins/mainwp-child/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0460/

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.