CVE-2026-13253: Wpxpo Post Grid Gutenberg Blocks – Postx

Medium severity, CVSS 6.4. EPSS: 0.4% chance of exploitation in the next 30 days.

The Ultimate Post plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'moreResultsText' block attribute of the ultimate-post/advanced-search block in versions up to and including 5.0.31. This is due to insufficient input sanitization and output escaping in the Advanced_Search::content() render callback: the attribute value is filtered with wp_kses(), which strips disallowed HTML tags but does NOT escape HTML special characters such as double quotes in plain text, and the result is then concatenated directly into the data-viewmoretext HTML attribute without esc_attr(). 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.

Affected products

• Wpxpo Post Grid Gutenberg Blocks – Postx: up to and including 5.0.31

Published 2026-07-09. Last modified 2026-07-09.