XSS in Stylemix Masterstudy Lms WordPress Plugin – For Online Courses And Education

CVE-2026-0559

The MasterStudy LMS WordPress Plugin – for Online Courses and Education plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'stm_lms_courses_grid_display' shortcode in all versions up to, and including, 3.7.11 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (9.7th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 9.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-0559: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-0559?
CVE-2026-0559 is a medium-severity vulnerability in Stylemix Masterstudy Lms WordPress Plugin – For Online Courses And Education, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-02-14.
How severe is CVE-2026-0559?
Medium severity. CVSS v3 base score is 6.4 out of 10.