XSS in Wpinsider-1 Simple Membership

CVE-2026-103427

The Simple Membership plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'country' parameter in all versions up to, and including, 4.8.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Unauthenticated attackers may also exploit this vulnerability when the plugin's Enable Free Membership feature is turned on, as it permits anonymous front-end registration and profile submission.

Vulnerability class: XSS (Cross-Site Scripting)

Published .

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

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-2026-103427?
CVE-2026-103427 is a medium-severity vulnerability in Wpinsider-1 Simple Membership, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-10-10.
How severe is CVE-2026-103427?
Medium severity. CVSS v3 base score is 6.4 out of 10.