CVE-2025-31885 Overview
CVE-2025-31885 is a DOM-based Cross-Site Scripting (XSS) vulnerability in the Daniel Floeter Hyperlink Group Block plugin for WordPress. The flaw affects all versions of hyperlink-group-block from initial release through 2.0.1. The plugin fails to properly neutralize user-controlled input during web page generation, allowing attackers to inject malicious scripts that execute in a victim's browser. Exploitation requires low-privileged authenticated access and user interaction. Successful attacks can lead to session hijacking, credential theft, and unauthorized actions performed under the victim's account. The vulnerability is categorized under [CWE-79] (Improper Neutralization of Input During Web Page Generation).
Critical Impact
Authenticated attackers with contributor-level access can inject persistent scripts that execute in administrators' browsers, enabling account takeover and site compromise.
Affected Products
- Daniel Floeter Hyperlink Group Block plugin for WordPress
- All versions from initial release through 2.0.1
- WordPress installations using the hyperlink-group-block plugin
Discovery Timeline
- 2025-04-01 - CVE-2025-31885 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-31885
Vulnerability Analysis
The vulnerability resides in the client-side rendering logic of the Hyperlink Group Block plugin. The plugin processes user-supplied attributes and injects them into the Document Object Model (DOM) without adequate sanitization or output encoding. When a browser parses attacker-controlled content, embedded JavaScript payloads execute in the context of the WordPress site.
DOM-based XSS differs from reflected or stored XSS because the payload never needs to traverse the server. The vulnerable JavaScript reads attacker-influenced data from the block attributes and writes it directly into a sink such as innerHTML or document.write. This client-side sink triggers script execution when the block renders.
The scope-changed impact reflects that scripts execute in the browser's trust context of the WordPress site, potentially crossing security boundaries between the plugin and other site components. See the Patchstack XSS Vulnerability Report for technical details.
Root Cause
The root cause is the plugin's failure to apply context-appropriate escaping to user-supplied data before writing it to a DOM sink. WordPress provides helpers such as wp_kses and esc_attr for output encoding, but the plugin does not consistently apply them within its Gutenberg block rendering code.
Attack Vector
An authenticated attacker with the ability to insert or modify Hyperlink Group Block content crafts a payload containing malicious JavaScript. The attacker publishes or previews the content. When another user (typically an administrator) views the affected page, the payload executes in their browser session.
Exploitation requires user interaction and low-level authenticated privileges. The attacker cannot exploit the flaw without a valid account capable of editing block content.
Detection Methods for CVE-2025-31885
Indicators of Compromise
- Unexpected <script> tags, javascript: URIs, or event handler attributes (onerror, onload) embedded in posts or pages using the Hyperlink Group Block
- New or unexpected WordPress administrator accounts created shortly after a contributor submitted block content
- Outbound HTTP requests from admin browser sessions to unfamiliar domains during page previews
- Modifications to plugin, theme, or user records that do not correspond to legitimate administrator activity
Detection Strategies
- Audit WordPress posts and postmeta tables for block markup containing suspicious HTML attributes or encoded script payloads
- Review the plugin version installed across managed WordPress sites and flag any instance at or below 2.0.1
- Correlate contributor-level content submissions with subsequent administrator session anomalies
Monitoring Recommendations
- Enable WordPress activity logging to capture block edits, user role changes, and plugin modifications
- Deploy a web application firewall (WAF) with rules to inspect POST payloads targeting the block editor REST endpoints
- Monitor browser-side Content Security Policy (CSP) violation reports for inline script execution attempts
How to Mitigate CVE-2025-31885
Immediate Actions Required
- Identify all WordPress instances running the Hyperlink Group Block plugin at version 2.0.1 or earlier
- Restrict contributor and author account creation until a patched version is applied
- Review recent content submissions from low-privileged users for embedded scripts or suspicious markup
- Rotate administrator credentials and invalidate active sessions if exploitation is suspected
Patch Information
At the time of NVD publication, the vulnerability affects all versions through 2.0.1. Administrators should consult the Patchstack advisory and the plugin's WordPress.org repository for the latest fixed release.
Workarounds
- Deactivate and remove the Hyperlink Group Block plugin until a patched version is available
- Enforce a strict Content Security Policy that disallows inline scripts and untrusted origins
- Limit block editing privileges to trusted users and disable contributor-level submissions where feasible
- Deploy a WAF rule set that blocks common XSS payload patterns in block editor requests
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.