What the vulnerability does
01Description
The Content Blocks (Custom Post Widget) plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's content_block shortcode in all versions up to, and including, 3.3.9 due to insufficient input sanitization and output escaping on user supplied values consumed from user-created content blocks. 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.
Explanation of Vulnerability in Simple Terms
02Summary
Content Blocks (Custom Post Widget) versions 3.3.9 and earlier contain a cross-site scripting vulnerability. An authenticated user with low privileges can inject malicious scripts that execute in other users' browsers, including site administrators. The vulnerability affects the scope beyond the vulnerable component itself, potentially compromising site security and user data.
What an attacker can do
03Attacker Capabilities
Inject malicious scripts that run in other users' browsers, including administrators.
Potential impact on your site
04Site Impact
Authenticated attackers can steal admin session tokens, modify site content, or perform actions as other users.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privilege authenticated account on the site.
Key dates
06Disclosure timeline
April 18, 2026
CVE published
April 20, 2026
Record updated
