CVE-2026-13295: Page Builder by SiteOrigin <= 2.34.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via panels_data Parameter

The Page Builder by SiteOrigin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via panelsdata Parameter in all versions up to, and including, 2.34.3 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. This is possible because the nonce and editpost capability checks enforced during save are both satisfied by Contributor-level users for their own posts, and the panelsdata value is stored as post meta — outside the scope of WordPress's unfilteredhtml carve-out — meaning no wpkses fallback prevents the unsanitized WPWidgetCustomHTML content from being persisted and later rendered verbatim on the frontend.