CVE-2026-18742
Flatsome <= 3.20.12 - Authenticated (Contributor+) DOM-Based Stored Cross-Site Scripting via 'data-text-sec', 'data-title', and 'title' Attributes via Custom HTML Block
The Flatsome theme for WordPress is vulnerable to Stored Cross-Site Scripting via 'data-text-sec', 'data-title', and 'title' Attributes via Custom HTML Block in all versions up to, and including, 3.20.12 due to insufficient input sanitization and output escaping. 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. The payload survives server-side sanitization because wp_kses_post permits data-* attributes globally via _wp_add_global_attributes, allowing attacker-controlled values in data-text-sec, data-title, and title attributes to persist in saved post content and be later interpreted as HTML by the ux-countdown, scroll-to, and lightbox-gallery JavaScript behaviors.
| CWE | CWE-79 |
| Vendor | ux-themes |
| Product | flatsome |
| Published | Nov 14, 2026 |
Get instant alerts for ux-themes flatsome
Be the first to know when new medium vulnerabilities affecting ux-themes flatsome are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N