XSS in Expresstech Quiz And Survey Master (Qsm) – Maker &

CVE-2026-96558

The Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the 'qsm_hidden_questions' parameter in all versions up to, and including, 11.2.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the attacker to force the mlw_results INSERT to fail by submitting an over-length or duplicate qsm_unique_key value, which triggers the audit trail code branch that writes the unescaped payload to wp_mlw_qm_audit_trail.form_data.

Vulnerability class: XSS (Cross-Site Scripting)

Published .

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-96558?
CVE-2026-96558 is a high-severity vulnerability in Expresstech Quiz And Survey Master (Qsm) – Maker &, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-10-10.
How severe is CVE-2026-96558?
High severity. CVSS v3 base score is 7.2 out of 10.