XSS in Livecomposer Live Composer – Free WordPress Website Builder

CVE-2026-16778

The Live Composer – Free WordPress Website Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'dslc_module_downloads_output' Shortcode Content in all versions up to, and including, 2.1.21 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 save-time wp_kses_post check is bypassed because the payload is stored as a serialized string containing no HTML tags for kses to tokenize, and the shortcode callback re-emits attacker-controlled values — including view_all_link (href attribute), main_heading_title (h2 body), button_text (anchor body), and button_inline_svg (anchor body) — without any escaping at render time.

Vulnerability class: XSS (Cross-Site Scripting)

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.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-16778?
CVE-2026-16778 is a medium-severity vulnerability in Livecomposer Live Composer – Free WordPress Website Builder, classified under Cross-site Scripting. CVSS score: 6.4/10. Published 2026-09-22.
How severe is CVE-2026-16778?
Medium severity. CVSS v3 base score is 6.4 out of 10.