CVE-2026-104392

Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker <= 11.2.7 - Authenticated (Contributor+) PHP Object Injection

2026-10-07 00:00
Ananda Dhakal

Strategic Overview

Status
Patched in 11.2.8
Affected Plugin
Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker
Affected Version
<= 11.2.7
CVSS
7.5High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2026-104392
View all Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker vulnerabilities

At a glance

CVE-2026-104392 is a high-severity Deserialization of Untrusted Data vulnerability in the Quiz and Survey Master (QSM) WordPress plugin, affecting versions <= 11.2.7. It carries a CVSS score of 7.5 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 11.2.8; sites on affected versions should update now. Disclosed October 2026, reported by Ananda Dhakal.

Vulnerability Overview

The Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 11.2.7. This is due to deserialization of untrusted input. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a PHP Object. 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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

Reaching this weakness in Quiz and Survey Master (QSM) <= 11.2.7 takes an account at Contributor level or above. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For Quiz and Survey Master (QSM) the fix is 11.2.8: builds <= 11.2.7 are affected, anything from 11.2.8 onward is not.

Remediation

Update to version 11.2.8, or a newer patched version

How does WordSec protect against this?

An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Quiz and Survey Master (QSM) 11.2.8 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-104392https://www.wordfence.com/threat-intel/vulnerabilities/id/1f55296d-f459-4bd4-979e-5286cc489159https://nvd.nist.gov/vuln/detail/CVE-2026-104392

Related records

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