Masteriyo instructor quiz content permits stored XSS
Masteriyo LMS before 2.3.3 allows an Instructor to store script-capable content in an affected quiz field. On a normal single-site installation, Masteriyo grants instructors unfiltered HTML, so the payload can execute when another user views the quiz. Multisite installations and sites defining DISALLOW_UNFILTERED_HTML are not affected by this specific path.
- Component
- Masteriyo LMS
- Plugin slug
learning-management-system- Affected
- < 2.3.3
- Safe version
2.3.3- Published
- Aug 16, 2026
This CVE was published Aug 16, 2026 and is one of 19 known issues for this plugin.
Update, patch or deactivate.
Update to 2.3.3 or later, inspect instructor-authored quiz content, and invalidate privileged sessions if a malicious quiz was viewed.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical description
The Masteriyo LMS WordPress plugin before 2.3.3 does not sanitise and escape a quiz field before outputting it back in a page, and grants its instructor role the ability to store unfiltered HTML, allowing such users to perform Stored Cross-Site Scripting attacks against any visitor of the affected page, including administrators. This affects default single-site installations. Sites running multisite, or defining DISALLOW_UNFILTERED_HTML, are not affected as the capability is not granted there.
CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N