Plugin Name	Bold Page Builder
Type of Vulnerability	Cross-Site Scripting (XSS)
CVE Number	CVE-2025-66057
Urgency	Low
CVE Publish Date	2025-11-29
Source URL	CVE-2025-66057

Urgent Security Notice: Bold Page Builder (≤ 5.5.2) Stored XSS (CVE-2025-66057) — Essential Guidance for WordPress Site Owners

Published: 27 November 2025
Author: Managed-WP Security Team

A critical security disclosure reveals a Stored Cross-Site Scripting (XSS) vulnerability impacting the Bold Page Builder WordPress plugin, versions 5.5.2 and earlier (CVE-2025-66057). This flaw permits users with Contributor-level access to inject persistent malicious HTML/JavaScript code that executes within the browsers of site visitors, including administrators. Although version 5.5.3 of the plugin contains vendor patches, many WordPress sites remain vulnerable due to delayed updates or compatibility concerns.

This comprehensive briefing is crafted for WordPress site owners, administrators, developers, and security professionals requiring clear, actionable steps to detect, mitigate, and neutralize this vulnerability until official updates can be applied.

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Executive Summary

• Vulnerability: Stored Cross-Site Scripting (XSS) in Bold Page Builder ≤ 5.5.2 (CVE-2025-66057).
• Impact: Arbitrary JavaScript/HTML injection leading to potential session hijacking, account takeover, drive-by redirects, or malicious content delivery.
• Privilege Level: Contributor role — low-level privileges sufficient for exploitation.
• CVSS Score: 6.5 (medium severity; vendor classifies priority as “Low”).
• Immediate Recommendation: Upgrade to version 5.5.3 or later ASAP. When immediate upgrading is not feasible, deploy Web Application Firewall (WAF) rules, implement virtual patching, and restrict access rights.
• Managed-WP Protection: Includes tailored WAF rules, virtual patching capabilities, continuous scanning for injected payloads, and malware risk mitigation available on our Basic and advanced plans.

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Why This Stored XSS Deserves Immediate Attention Despite “Low” Priority

CVSS scores provide initial guidance but don’t capture operational risk entirely. Key concerns include:

• Contributor-level access is common: Roles such as guest authors, editors, or compromised accounts often hold these permissions, making exploitation vectors broad.
• Persistence and impact: Stored XSS payloads reside in the database and execute automatically for all visitors including privileged users, increasing the threat surface exponentially.
• Attack escalation: Malicious actors can leverage this vulnerability to hijack sessions, escalate privileges, deploy drive-by attacks, or poison SEO via malicious redirects or cryptomining scripts.
• Interplay with other plugins/themes: If additional plugins render this content in the admin panel, payload execution risk increases for backend users.

Bottom line: Do not underestimate stored XSS vulnerabilities. Immediate mitigation and remediation are critical to preserving site integrity and reputation.

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Technical Cause Overview

While implementation details are vendor-specific, stored XSS in page builders commonly arise from:

• Improper sanitization and output encoding of user-supplied content fields.
• Usage of raw HTML content blocks without validation or role restrictions.
• Reliance on client-side validation without rigorous server-side checks.
• Insufficient filtering of event attributes (e.g., onload, onclick) and encoded payloads (base64, hex).

This vulnerability allows contributors to place unsanitized script payloads that persist and are rendered unfiltered on public and admin pages.

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Who Is at Risk?

• Sites running Bold Page Builder version 5.5.2 or earlier.
• Sites allowing Contributors or similar low-privilege users to edit content.
• Sites permitting user-generated content or submissions stored in pages or posts.
• Multisite setups with network-activated Bold Page Builder where multiple user accounts exist.

If your WordPress deployment uses Bold Page Builder, assume risk exists until you verify updates and mitigations.

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Immediate Action Checklist (Next 1–2 Hours)

1. Verify plugin version:
   – Via Dashboard: Plugins → Bold Page Builder → Check version.
   – Via WP-CLI:

   wp plugin get bold-page-builder --field=version

2. If ≤ 5.5.2: Schedule an immediate plugin update to 5.5.3 or higher.
   If immediate update is blocked by compatibility or testing, proceed with mitigations below without delay.
3. Restrict editor access:
   – Temporarily revoke Contributor/Author editing privileges.
   – Disable or downgrade contributor accounts to reduce risk.
4. Activate WAF / virtual patching:
   – Enable Managed-WP’s WAF tailored rules preventing Bold Page Builder XSS exploitation.
5. Scan content for malicious payloads:
   – Search for script tags, inline event attributes, and encoded scripts in posts and meta.
6. Enhance admin security:
   – Enforce two-factor authentication (2FA) for admin/editor accounts.
   – Rotate passwords for all relevant accounts if breach suspected.
7. Back up site:
   – Take a full export (database + files) before making further changes.

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Detection Techniques for Stored XSS Payloads

Look for common XSS indicators: <script> tags, inline event handlers (onload, onclick), javascript: URIs, and base64-encoded scripts. Use queries similar to these:

-- Detect <script> in post content
SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%<script%';

-- Detect inline event handlers
SELECT ID, post_title FROM wp_posts WHERE post_content REGEXP 'on(click|load|error|mouseover|mouseenter)';

-- Check wp_postmeta table for scripts
SELECT post_id, meta_key FROM wp_postmeta WHERE meta_value LIKE '%<script%';

-- Search encoded payloads (base64)
SELECT post_id, meta_key FROM wp_postmeta WHERE meta_value LIKE '%base64,%';

Use Managed-WP’s malware scanner to automate these detections and flag suspicious content.

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Containment and Remediation Steps

1. Isolate and remove payloads:
   – Edit or replace posts with malicious content.
   – With backups and caution, run sanitized SQL commands to strip script tags.
   Example:

   UPDATE wp_posts SET post_content = REPLACE(post_content, '<script', '<!--xss-blocked<script') WHERE post_content LIKE '%<script%';

   Note: Prefer manual or DOM-based sanitization to avoid content breakage.

2. Invalidate active sessions:
   Force logout all users by resetting authorization keys or using session management plugins.
3. Rotate credentials:
   Reset all admin/editor/FTP/database passwords and revoke API keys if compromised.
4. Perform full-site malware scan:
   Confirm no backdoors or injected PHP/webshells remain.
5. Audit user accounts:
   Identify and remove suspicious users and review recent edits and login IPs.
6. Restore from clean backup if needed:
   If cleanup is overly complex or incomplete, revert to a verified clean state.

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Preventive Hardening Best Practices

• Apply the principle of least privilege: limit Contributor role capabilities wherever possible.
• Disable Raw HTML blocks or similar elements for untrusted users in page builders.
• Developers should implement robust server-side input sanitization with WordPress APIs (e.g., wp_kses_post(), esc_html()).
• Implement Content Security Policy (CSP) headers to reduce XSS impacts.
• Maintain routine patching workflows — test plugin updates on staging environments before production deploy.
• Deploy Managed-WP’s WAF to provide ongoing virtual patching until updates are complete.

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Technical WAF Rules for Immediate Deployment

If patching is delayed, use these ModSecurity-compatible sample rules as a starting point to block common exploitation vectors:

Block literal <script> tags

SecRule REQUEST_BODY "@rx (?i)<\s*script" \
    "id:100001,phase:2,deny,log,msg:'Blocked XSS script tag in request body'"

Block javascript: and data: URIs

SecRule REQUEST_BODY "@rx (?i)javascript\s*:" \
    "id:100002,phase:2,deny,log,msg:'Blocked javascript: URI in request body'"
SecRule REQUEST_BODY "@rx (?i)data\s*:\s*text/html|data\s*:\s*application/javascript" \
    "id:100003,phase:2,deny,log,msg:'Blocked data: URI in request body'"

Block inline event handlers

SecRule REQUEST_BODY "@rx (?i)on(click|load|error|mouseover|mouseenter|submit)\s*=" \
    "id:100004,phase:2,deny,log,msg:'Blocked inline event handler in request body'"

Block encoded <script> tags and base64 payloads

SecRule REQUEST_BODY "@rx (?i)(%3C|\\u003c).*script|base64\,[A-Za-z0-9+/]{20,}" \
    "id:100005,phase:2,deny,log,msg:'Blocked encoded script or base64 payload'"

Note: Configure exceptions carefully for trusted admin paths to reduce false positives, and always monitor logs for tuning.

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Safe Testing for Vulnerability Presence

Never test exploit payloads on live environments. Use staging or local copies for testing.

• Insert a harmless marker string (e.g., <!--XSS-TEST-12345-->) into content via a Contributor account and verify if it renders unsanitized on the front end.
• For more advanced testing, use non-destructive payloads like:

  <img src=x onerror="console.log('XSS TEST')">

Limit testing to non-production environments only.

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Incident Response Playbook

1. Put the site into maintenance mode to prevent further harm.
2. Preserve snapshots and logs for forensic analysis.
3. Remove all detected malicious content from the database.
4. Invalidate user sessions and rotate credentials.
5. Complete malware and file integrity scans.
6. Restore a clean backup if needed.
7. Notify impacted stakeholders per compliance requirements.
8. Conduct root cause analysis and apply additional hardening.

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Example Forensic Queries & Log Review Tips

• Analyze server access logs for unusual POST requests to editor endpoints during vulnerability disclosure period.
• Review WAF logs for blocked requests with script or suspicious payload signatures.
• Correlate newly created or updated posts by Contributors with suspicious content timestamps.

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Developer Guidance for Eliminating XSS Risks

• Always sanitize user input and escape output using WordPress sanitization functions.
• Restrict capabilities to submit raw HTML to trusted users only.
• Validate and normalize inputs strictly at the server side.
• Use parameterized data structures that separate code from content.
• Leverage CSP headers for defense-in-depth against script injection.
• Employ automated security testing (SAST, dependency analysis) in CI pipelines.
• Maintain mechanisms for virtual patching policies aligned with security disclosure timeline.

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How Managed-WP Protects Your Site

At Managed-WP, we recognize stored XSS vulnerabilities as severe operational risks requiring layered part-proactive, part-reactive controls beyond standard patching.

• Custom WAF Rules: Tailored signatures blocking Bold Page Builder exploit patterns.
• Virtual Patching: Rapid deployment of protective WAF signatures as soon as vulnerabilities are disclosed.
• Automated Scanning: Continuous detection of suspicious payloads and malware in posts and meta.
• Role-Based Hardening Recommendations: Alerts on risky permissions and editing roles.
• Expert Incident Support: Live guidance for containment and cleanup during suspected attacks.

Managed-WP Basic Plan (free and higher tiers) already provides firewall, WAF, malware scanning, and mitigations aligned to OWASP Top 10 risks — critical layers to keep your site secure while you patch.

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Immediate Practical Next Steps

• Update Bold Page Builder to version 5.5.3 without delay.
• If immediate update isn’t possible:
  • Enable Managed-WP WAF with Bold Page Builder XSS rules.
  • Restrict Contributors and Authors’ edit capabilities temporarily.
  • Run targeted content scans for XSS payloads and encoded payloads.
  • Force admin logouts and rotate all relevant credentials.
  • Deploy and test Content Security Policy headers cautiously.
• After patching, perform comprehensive scans and monitor logs vigilantly for at least 30 days.

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Detection Signatures for Your Security Team

Apply these patterns in your scanning tools or WAF:

• <\s*script\b – detects <script> tags.
• on(click|error|load|mouseover|mouseenter|submit)\s*= – inline event handlers.
• javascript\s*: – javascript: URIs.
• data:\s*text/html|data:\s*application/javascript – data URIs.
• base64,[A-Za-z0-9+/]{50,} – base64 blobs.
• \\u003c or %3C followed by script – encoded script tags.

Tune these carefully to minimize false positives and validate before deployment.

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Verification Post-Patching

1. Confirm plugin version is 5.5.3 or later.
2. Run full malware and content scanning to ensure no residual payloads remain.
3. Review WAF and server logs for persistent or new attack attempts.
4. Monitor error logs and access logs for suspicious activity.
5. Conduct a post-mortem to validate remediation and improve defenses.

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Frequently Asked Questions

Q: No Contributors on my site; am I safe?
A: Reducing untrusted editors lowers risk significantly. However, malicious input can come from plugins or imported content. Maintain scanning and WAF protections.

Q: My site customization prevents immediate updates. Best options?
A: Activate Managed-WP’s WAF virtual patches, restrict editing roles, scan for and remove malicious content, and plan staged updates tested in safe environments.

Q: Will CSP completely stop XSS?
A: CSP helps reduce exposure but is not a silver bullet; combine CSP with sanitization, WAF, and proper access controls.

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Final Recommendations from Managed-WP

Stored XSS in page builders directly impacts site content and can be weaponized to compromise administrative accounts, visitor trust, SEO ranking, and brand reputation. Managed-WP advises immediate plugin updates and layered defenses: strict permission controls, code sanitization, specialized WAF rules, and continuous monitoring.

If you need assistance with virtual patch deployments or comprehensive site scanning, Managed-WP’s team is ready to support you—start with our Basic Plan for managed firewall and scanning today:

https://managed-wp.com/pricing

Stay vigilant, patch early, and maintain defense-in-depth — protect your WordPress site and business.

— Managed-WP Security Team

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