EUVD-2026-23670Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
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.
AnalysisAI
Stored Cross-Site Scripting in Content Blocks (Custom Post Widget) plugin for WordPress affects all versions up to 3.3.9, allowing authenticated contributors and above to inject arbitrary JavaScript via the content_block shortcode that executes in the browsers of all users viewing affected pages. The vulnerability stems from insufficient input sanitization and output escaping; no public exploit code or active exploitation has been identified at the time of analysis, but the low attack complexity and broad scope (cross-site) make this a significant risk for WordPress sites with untrusted contributor accounts.
Technical ContextAI
The Content Blocks (Custom Post Widget) plugin extends WordPress functionality through custom shortcodes, specifically the content_block shortcode, which dynamically renders user-supplied content. The underlying weakness (CWE-79: Improper Neutralization of Input During Web Page Generation) indicates the plugin fails to properly sanitize user input before storage (stored XSS vector) or escape output when rendering shortcode content, violating WordPress security best practices via the sanitize_text_field() and wp_kses_post() functions. The CPE identifier cpe:2.3:a:vanderwijk:content_blocks_(custom_post_widget) confirms the affected product is maintained by vanderwijk and distributed through the official WordPress plugin repository.
RemediationAI
Upgrade the Content Blocks (Custom Post Widget) plugin to version 3.4.0 or later, which includes patches for input sanitization and output escaping. Administrators should navigate to the WordPress Plugins dashboard, locate the Content Blocks plugin, and apply the update immediately. For organizations unable to update immediately, restrict the 'contributor' and 'author' WordPress role permissions to prevent creation or editing of content blocks via the 'content_block' shortcode capability (via role editor plugins such as User Role Editor), or temporarily disable the plugin if not actively in use. A secondary mitigation is to audit all existing content blocks created before the patch for injected scripts and remove suspicious shortcodes, though this is labor-intensive for sites with many blocks. Disable the plugin entirely if contributor-level users are untrusted or if custom code review is unavailable.
Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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