CVE-2026-16778: XSS (CVSS 6.4)

Description

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.

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CVSS v3.1 Score

6.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.12%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2026-16778? +

CVE-2026-16778 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0022, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-16778? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-16778