CVE-2025-11162 Overview
CVE-2025-11162 is a Stored Cross-Site Scripting (XSS) vulnerability in the Spectra Gutenberg Blocks – Website Builder for the Block Editor plugin for WordPress. The flaw affects all plugin versions up to and including 2.19.14. It stems from insufficient input sanitization and output escaping in the Custom CSS feature. Authenticated users with Contributor-level access or higher can inject arbitrary web scripts into pages. The injected payload executes in the browser of any visitor who accesses an affected page, enabling session theft, redirection, or defacement in the context of the site.
Critical Impact
Contributor-level accounts can inject persistent JavaScript that executes against every visitor of an affected WordPress page, including administrators.
Affected Products
- Spectra Gutenberg Blocks – Website Builder for the Block Editor (Ultimate Addons for Gutenberg) plugin for WordPress
- All versions up to and including 2.19.14
- WordPress sites permitting Contributor-level (or higher) accounts to author content with Spectra blocks
Discovery Timeline
- 2025-11-05 - CVE-2025-11162 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-11162
Vulnerability Analysis
The vulnerability is a stored XSS classified under [CWE-79]. Spectra provides a Custom CSS block feature that allows post authors to attach CSS rules to their content. The plugin fails to properly sanitize author-supplied CSS input and does not escape values on output when the CSS is rendered into the page. An authenticated attacker holding at least Contributor privileges can embed script-executing payloads through this field. Once the post is viewed, the payload runs in the visitor's browser under the site's origin. Because Contributor accounts are commonly delegated on multi-author WordPress sites, the privilege barrier is low relative to the impact.
Root Cause
The root cause is missing input sanitization and output escaping around Custom CSS handling in the plugin's asset generation code paths. Relevant code paths reside in classes/class-uagb-loader.php and classes/class-uagb-post-assets.php in the 2.19.14 tag. Attacker-supplied content is trusted and emitted into the rendered page context without sufficient filtering to prevent script execution.
Attack Vector
Exploitation requires network access to the WordPress site and authenticated access with Contributor-level permissions or above. The attacker authors or edits a post that uses the Spectra Custom CSS capability, injects a crafted payload, and submits or publishes the content. When any user, including administrators, opens the affected page, the injected script executes with the site's origin. This scope change enables session hijacking, forced administrative actions via CSRF-style requests, and content manipulation.
No verified public exploit code is available. See the Wordfence Vulnerability Report and code references for class-uagb-loader.php and class-uagb-post-assets.php for the affected code locations.
Detection Methods for CVE-2025-11162
Indicators of Compromise
- Post or page metadata containing Spectra Custom CSS values that include <script>, onerror=, onload=, javascript:, or unusual expression() constructs.
- Unexpected outbound requests from visitor browsers to attacker-controlled domains sourced from pages using Spectra blocks.
- New or modified posts by Contributor-level accounts that contain HTML entities or unicode escapes designed to bypass CSS filtering.
Detection Strategies
- Audit the wp_postmeta and Spectra block attributes tables for Custom CSS values and flag entries containing HTML tags or JavaScript event handlers.
- Review WordPress audit logs for edits by Contributor and Author roles against posts that include Ultimate Addons for Gutenberg blocks.
- Deploy a WAF rule that inspects post save requests for script-like content in Spectra block payloads.
Monitoring Recommendations
- Monitor administrator session activity for anomalous authenticated actions immediately following visits to author-created pages.
- Alert on installations of the Spectra plugin at or below version 2.19.14 across managed WordPress fleets.
- Track browser-side Content Security Policy (CSP) violation reports for inline script executions on Spectra-rendered pages.
How to Mitigate CVE-2025-11162
Immediate Actions Required
- Update the Spectra Gutenberg Blocks plugin to a version later than 2.19.14 as soon as the vendor-fixed release is available.
- Audit existing posts authored by Contributor and Author accounts for malicious Custom CSS payloads and remove offending content.
- Rotate administrator sessions and credentials if evidence of script execution against privileged users exists.
Patch Information
Refer to the Wordfence Vulnerability Report for the current fixed version. Apply plugin updates through the WordPress admin interface or via wp-cli. Verify the installed version after update by inspecting the plugin header or running wp plugin get ultimate-addons-for-gutenberg.
Workarounds
- Restrict the Contributor and Author roles from using the Spectra Custom CSS block via a role-capability plugin until a patch is applied.
- Enforce a strict Content Security Policy that disallows inline scripts and unsafe CSS expressions on public pages.
- Temporarily disable the Spectra plugin on high-value sites if immediate patching is not feasible.
# Update the plugin via WP-CLI
wp plugin update ultimate-addons-for-gutenberg
wp plugin get ultimate-addons-for-gutenberg --field=version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
