CVE-2026-109989: Themify Popup <= 1.4.7 - Authenticated (Author+) Stored Cross-Site Scripting via 'popup_width_unit' Parameter

Severity: medium (CVSS 6.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-17 · updated 2026-10-19
Weakness: CWE-79

Description

The Themify Popup plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'popup_width_unit' parameter in all versions up to, and including, 1.4.7 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Affected products

themifyme Themify Popup: through 1.4.7

References

https://plugins.trac.wordpress.org/browser/themify-popup/tags/1.4.7/includes/themify-metabox/includes/themify-metabox-core.php#L151
https://plugins.trac.wordpress.org/browser/themify-popup/tags/1.4.7/includes/themify-metabox/includes/themify-metabox-core.php#L209
https://plugins.trac.wordpress.org/browser/themify-popup/tags/1.4.7/views/styles.php#L29
https://plugins.trac.wordpress.org/changeset?reponame=&old=3749602%40themify-popup&new=3749602%40themify-popup
https://www.wordfence.com/threat-intel/vulnerabilities/id/da003985-7fb2-4f5b-bb70-6ec3578ef3e8?source=cve

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