Post Grid Gutenberg Blocks for News, Magazines, Blog Websites <= 5.0.31 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'moreResultsText' Block Attribute

Summary

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.

Timeline

1. Jul 9, 2026, 6:52 AM UTCCVE published
2. Jul 9, 2026, 5:32 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Jul 9, 2026, 5:33 PM UTCRecord last updated

Affected versions

• wpxpo Post Grid Gutenberg Blocks – PostX

  through 5.0.31

References 8