# Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker <= 11.2.8 - Authenticated (Contributor+) PHP Object Injection via Quiz Contact Tab Settings

- **ID:** WPSEC-2026-1583
- **Plugin:** Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker (`quiz-master-next`), https://wordpress.org/plugins/quiz-master-next/
- **Affected versions:** all versions before 11.2.9
- **Fixed in:** 11.2.9 (Update to 11.2.9 or later.)
- **Severity:** High 8.8 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **Weakness:** CWE-502
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-10-24)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/quiz-master-next
- **Fix released:** 2026-10-23
- **Published:** 2026-10-24
- **URL:** https://wpsec.com/vuln/WPSEC-2026-1583/

## Description

The Quiz and Survey Master (QSM) plugin for WordPress is vulnerable to PHP Object Injection via the quiz Contact tab settings (the qsm_save_contact AJAX action) in all versions up to, and including, 11.2.8, due to the handler writing any submitted key into the quiz options, including 'select_category_question', which is later passed to maybe_unserialize() when the quiz is loaded on the front end. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject a serialized PHP object into a quiz they own. No known POP chain is present in the vulnerable software. If a POP chain is present via an additional 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-2026-1583/
- https://plugins.svn.wordpress.org/quiz-master-next/tags/11.2.9/
- https://wordpress.org/plugins/quiz-master-next/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1583/

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.