Plugin Name	Booking Calendar
Type of Vulnerability	Information Disclosure
CVE Number	CVE-2025-14146
Urgency	Low
CVE Publish Date	2026-01-08
Source URL	CVE-2025-14146

Sensitive Data Exposure in Booking Calendar (≤ 10.14.10) — What WordPress Site Owners Need to Know and How WP-Firewall Protects You

Author: WP-Firewall Security Team
Date: 2026-01-09

On 8 January 2026 a security researcher reported a sensitive information exposure vulnerability in the popular WordPress plugin “Booking Calendar” affecting versions up to and including 10.14.10 (tracked as CVE-2025-14146). The plugin vendor released a patch in version 10.14.11 to address the issue.

We prepared this advisory from the point of view of a WordPress firewall and security provider. In this article I’ll walk you through:

• What this vulnerability is and who is impacted
• Practical risk assessment for WordPress sites using Booking Calendar
• Immediate steps you should take (including patching and short-term mitigations)
• How a web application firewall (WAF) like WP-Firewall can reduce risk quickly
• Incident response and recovery guidance if you suspect a compromise
• Detection signals and logging signatures to watch for
• Longer-term hardening and operational recommendations

This is written for WordPress site administrators, agencies, and hosting teams who need clear, actionable guidance — not a technical write-up intended to facilitate exploitation.

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Executive summary

• Vulnerability: Unauthenticated Sensitive Information Exposure in Booking Calendar (≤ 10.14.10) — CVE-2025-14146.
• Impact: Attackers could access information normally not available to unauthenticated visitors. The exposed data can include booking metadata, internal identifiers, and potentially personally identifiable information (PII) depending on your plugin configuration.
• Severity (practical): Low-to-Moderate on many installs. CVSS base score published is 5.3. However, the real-world impact depends on what data you collect and store (customer names, emails, phone numbers, payment references, internal notes).
• Fix: Upgrade Booking Calendar to 10.14.11 or later immediately.
• Interim controls: Disable the plugin if not essential, restrict access to booking-related endpoints, enable WAF virtual patching and rate limiting, audit logs for suspicious access patterns.
• Credits: Research reported by Filippo Decortes, Bitcube Security.

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What exactly does “sensitive information exposure” mean here?

Sensitive information exposure describes cases where an application unintentionally returns data that should be protected. In the case of this Booking Calendar issue the vulnerability allowed unauthenticated (not logged-in) users to view data that the plugin intended to keep private. That could include:

• Booking records (dates, times)
• Customer names, email addresses, phone numbers (depending on form configuration)
• Internal booking notes and status fields
• Internal identifiers or tokens that could be used to link to other records

Important: The vulnerability is an information disclosure. It does not by itself grant the ability to modify bookings or take over user accounts — but access to PII or internal IDs can enable targeted social engineering, cross-correlation with other data, or follow-up attacks against administrative users.

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Who should be worried?

• Any site running the Booking Calendar plugin at versions ≤ 10.14.10.
• Sites that collect PII via booking forms (names, phone numbers, emails, address).
• Agencies managing many client sites or hosts with multi-tenant installations.
• Sites covered by privacy regulations (GDPR, CCPA, etc.) — a data exposure could trigger notification obligations.

If you are running Booking Calendar, check your installed plugin version now. If you cannot patch immediately, treat the site as higher risk until mitigations are in place.

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Immediate actions — ordered, pragmatic steps

1. Verify your Booking Calendar version:
   • In the WordPress dashboard go to Plugins → Installed Plugins and check the installed version of Booking Calendar.
   • If you manage many sites, use your management tool or CLI (WP-CLI) to inventory versions.
2. Upgrade now (recommended):
   • Update Booking Calendar to 10.14.11 or later. The vendor has issued a fix in 10.14.11.
   • Test the update quickly on a staging environment if you have complex customizations, then push to production.
3. If you cannot update immediately, apply short-term mitigations:
   • Disable the plugin if you do not need booking functionality right now.
   • Restrict access to booking endpoints with IP allowlists (for internal tools) or by requiring authentication for access.
   • Use your WAF to virtually patch the vulnerability and block known malicious patterns (examples below).
4. Audit logs and search for indicators:
   • Look for abnormal numbers of requests to booking plugin endpoints, spikes in 200 responses from endpoints that normally require authentication, or unusual querystrings.
   • Preserve logs for potential forensic analysis.
5. Notify stakeholders:
   • If exposed data likely includes personal data, consult your privacy/compliance teams about notification requirements.
6. Rotate secrets if you detect misuse:
   • If you find evidence of data exfiltration or credential misuse, rotate API keys, integration passwords, and administrator passwords.

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Practical attack scenarios (realistic examples)

• Targeted data harvesting:
  An attacker harvests booking records (names, emails) and then uses the list for phishing campaigns or targeted scams.
• Reconnaissance leading to targeted social engineering:
  Exposed booking notes may contain hints about internal workflows or staff, enabling a tailored social engineering attempt against a receptionist or administrator.
• Data correlation and privacy impact:
  Aggregated bookings combined with other public information can be used to profile customers or employees.

Although this vulnerability does not directly escalate to remote code execution or admin takeover, the downstream effects of exposed PII can be significant for reputation and compliance.

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How WP-Firewall protects you: virtual patching, rules, and detection

At WP-Firewall we approach vulnerabilities like this using three complementary controls: rapid virtual patching (WAF rules), detection and alerting, and longer-term hardening.

1) Virtual patching (apply immediately)

Virtual patching means deploying WAF rules that block exploit attempts at the edge before they reach your application. Virtual patching is ideal when you cannot immediately apply vendor-supplied updates (e.g., large multisite deployments, complex staging/QA processes).

Suggested virtual patching actions for Booking Calendar exposure:

• Block unauthenticated access to booking-specific AJAX/admin endpoints unless the requester is an authenticated user or a known trusted IP.
• Enforce strict method checks: disallow HTTP methods that are not used by normal booking operations (e.g., PUT/DELETE on public endpoints).
• Rate-limit public requests to booking endpoints to stop large-scale scraping.

Example WAF rule logic (pseudocode, not vendor-specific):

• Rule 1 — Block suspicious GET requests to booking endpoints that return private data:
  • IF request URI matches regex: /wp-content/plugins/booking/|/booking-calendar/|/wp-admin/admin-ajax.php.*(action=.*booking.*|action=.*get_booking.*)
  • AND user is NOT authenticated (no valid WordPress login cookie)
  • THEN block or return 403
• Rule 2 — Rate limit:
  • IF request URI matches booking endpoints
  • AND requests per minute from IP > 30 (adjust to your normal traffic)
  • THEN throttle or block
• Rule 3 — Block known malicious patterns:
  • IF query string parameters appear to enumerate IDs (e.g., id= followed by a wide range of sequential values)
  • AND many different id values per IP in a short time
  • THEN challenge with CAPTCHA or block

Note: The exact endpoints may vary with plugin settings and customization. When possible use safe positive filtering (allow only known-good actions) rather than blacklisting.

2) Detection and alerting

Deploy WAF detection rules that don’t block immediately but alert your security team when certain patterns appear:

• Unusual volume of 200 responses for booking endpoints from one IP.
• Requests with empty or missing cookies to endpoints that should require authentication.
• Requests with unusual user-agents that are known scraping tools.

Set up alerts to email/SMS/Slack for immediate investigation.

3) Protection hardening by WP-Firewall features

If you run WP-Firewall, enable these capabilities:

• Managed firewall policies that include virtual patches for newly discovered vulnerabilities.
• Malware scanner and scheduled site scans for additional post-exploitation indicators.
• Rate limiting and automated bot mitigation.
• Auto virtual patching for vulnerable plugin versions (when available).
• Allowlisting/denylisting for admin access and sensitive endpoints.

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Detection and logging — what to monitor

If you want to determine whether your site has been probed or data was accessed, look for these signs in access logs and application logs:

• Increased access to booking-related URLs from single IPs or IP ranges.
• Large numbers of unique querystring values immediately returning 200 results for booking endpoints.
• Requests to admin-ajax.php with booking-related actions where the request lacks a valid authentication cookie.
• High volume of requests from a small set of IPs or IPs with poor reputation.
• Sudden spikes in database SELECT queries relating to booking tables at odd hours.
• User agent strings associated with known scrapers (but more often attackers will use browser-like strings).

A sample log search you can run (example for sysadmins):

• Search web server logs for suspicious patterns:

  grep -i "admin-ajax.php" access.log | grep -E "action=.*booking|action=.*get.*booking"

• Count per IP:

  awk '{print $1}' | sort | uniq -c | sort -nr | head

If you see many different IDs being requested in a short timeframe, that’s strong evidence of enumeration/scanning.

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Suggested WAF rule examples

Below are non-executable pseudocode examples and a ModSecurity-style rule that you can adapt to your environment. Do not paste these into production without testing — tailor them to your site traffic patterns.

Pseudocode rule (allowlist approach):

• Only allow access to booking endpoints if:
  • The request has a valid WordPress login cookie OR
  • The request originates from a trusted IP/range OR
  • The request has a known, valid referrer for public booking forms
• Else, return 403 or a challenge page.

ModSecurity-style example (illustrative):

# Block likely unauthenticated booking enumeration attempts
SecRule REQUEST_URI "@rx (/wp-content/plugins/booking/|/booking-calendar/|admin-ajax\.php.*(action=.*booking|action=.*get_booking))" \
  "id:100001,phase:1,pass,nolog,chain"
  SecRule &REQUEST_COOKIES:wordpress_logged_in_cookie "@eq 0" \
    "chain"
  SecRule REQUEST_METHOD "@streq GET" \
    "phase:2,deny,status:403,msg:'Block unauthenticated booking endpoint access',log"

Rate-limit example (pseudo):

# If more than 30 requests in 60s to booking endpoints by same IP -> throttle
If requests_to('/booking-endpoints') from IP > 30 in 60 seconds:
    return 429 or present CAPTCHA

Again, adapt thresholds to match normal traffic. For sites with public booking pages that must be public, use CAPTCHA challenges and rate-limiting rather than outright block.

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Hardening steps for WordPress admins

• Keep plugins and WordPress core up to date. Prioritize security updates.
• Minimize plugins: remove plugins you do not use. Fewer plugins = smaller attack surface.
• Enforce least privilege for WordPress accounts: only give people the permissions they need.
• Use strong admin passwords and enforce MFA for all administrator accounts.
• Disable debug/logging output on production sites (don’t leak stack traces).
• Review booking plugin settings: reduce collection of unnecessary PII, disable saving of sensitive fields that are not required.
• Regularly backup your site and database and test your restore process.
• Use staging environments to validate plugin upgrades before rolling them to production.

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Incident response if you suspect data exposure or compromise

1. Isolate:
   • If feasible, take the affected site into maintenance mode or temporarily disable the booking plugin to stop additional exposure.
2. Preserve evidence:
   • Archive web server and application logs and database snapshots in read-only media.
   • Do not overwrite logs — maintain chain-of-custody for forensic integrity if required.
3. Scan and inspect:
   • Run a full malware scan and integrity check (file changes, unknown cron jobs, new admin users).
   • Search database tables used by the booking plugin for unexpected rows or modified records.
4. Remediate:
   • Apply the booking plugin update (10.14.11+) in a controlled manner.
   • Rotate any API keys or credentials that might have been exposed.
   • Reset administrator passwords for high-privilege accounts.
5. Notify:
   • If customer PII is confirmed exposed, follow your legal/compliance obligations for breach notification.
   • Inform affected customers with clear guidance (what happened, what you are doing, any steps they should take).
6. Post-incident:
   • Conduct a root-cause analysis.
   • Strengthen monitoring and accelerate patch management processes.
   • Consider a security audit or third-party penetration test focused on the booking workflows.

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Recovery checklist (step-by-step)

• Upgrade Booking Calendar to 10.14.11 or later.
• Apply WAF virtual patching for booking endpoints (block/limit unauthenticated access).
• Search logs for suspicious booking endpoint access patterns; save results.
• If live data exposure confirmed: prepare customer communication and notify regulators if required.
• Rotate integration keys and change admin passwords.
• Run malware scan, compare file checksums against clean backups.
• Re-enable plugin only after monitoring indicates bad actors no longer probing endpoints.
• Conduct a security review of plugin settings and minimize PII collection.
• Schedule recurring security checks and automated updates where possible.

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Why virtual patching matters (real-world benefits)

For many organizations the biggest challenge is operations: applying every plugin update instantly across many sites is not always realistic. Virtual patching gives you time:

• It blocks exploit attempts at the edge so attackers never reach the vulnerable code.
• It allows you to coordinate a safe patch rollout (test in staging, run QA).
• It reduces the immediate blast radius while you perform a thorough incident response.

WP-Firewall provides virtual patching and managed rules so you don’t need to write and maintain custom ModSecurity rules yourself. That helps bridge the gap between disclosure and permanent remediation.

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How to balance availability and security for public booking pages

Many businesses need booking pages to remain fully public — that’s why blocking must be surgical:

• Prefer rate-limiting + CAPTCHA over hard blocks for public endpoints.
• Require tokenized or signed requests for AJAX/REST calls that fetch booking details.
• Consider short-lived booking tokens that expire quickly rather than permanent, guessable identifiers.
• Use server-side logic to ensure only the minimal necessary fields are returned to unauthenticated users.

Design your forms to minimize retention of unnecessary PII (for example, don’t store street addresses if you can avoid it).

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Monitoring and threat hunting playbook

If you run a security operations function, incorporate these searches and alerts:

• Alert: X requests to booking endpoints from same IP within Y minutes (tunable).
• Alert: More than Z unique booking IDs requested from same IP within Y minutes.
• Alert: Requests to booking endpoints resulting in 200 responses with personal data patterns (e.g., email addresses in response).
• Weekly check: Inventory plugins and versions on all managed sites — flag outdated Booking Calendar instances.
• Monthly: Run an automated privacy audit on booking forms to see what fields are being captured/stored.

Keep these detections integrated into your SIEM, Slack channels, or paging systems depending on severity.

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Communication and customer privacy considerations

If PII is involved, prepare a plain-language notice for affected users that covers:

• What happened and the timeframe
• What information may have been exposed (be specific but accurate)
• Actions the organization has taken (patching, virtual patching, investigation)
• Recommended steps for users (e.g., be aware of phishing, change passwords where appropriate)
• Contact details for further questions

Engage legal and compliance early. Privacy law obligations vary by jurisdiction and the type/volume of data exposed.

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Long-term risk management recommendations

• Implement automatic security update processes for low-risk plugins where possible.
• Maintain a prioritized inventory of plugins by criticality and data sensitivity.
• Add a staging validation step with automated tests for critical user flows (booking, checkout) so updates can be rolled back quickly if they break functionality.
• Schedule periodic third-party security assessments focusing on customer data handling and booking workflows.
• Provide security training for staff who manage plugins and site configurations.

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Final thoughts

This Booking Calendar information exposure is a reminder that even widely used plugins can contain logic or endpoints that expose data unintentionally. Patching is the best long-term remedy, but operational realities mean edge protections and response playbooks are the backbone of real-world security.

Make sure you:

• Confirm your plugin version and upgrade to 10.14.11 or later
• Use virtual patching and rate limiting to reduce immediate exposure
• Audit logs for indicators and retain evidence if you suspect data access
• Review booking form data practices to minimize future exposure

If you need help applying virtual patches quickly, or want managed monitoring and automated protections, WP-Firewall can step in to reduce risk while you coordinate updates.

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Useful checklist — what to do right now

• Confirm plugin version (Booking Calendar ≤ 10.14.10?).
• Upgrade to Booking Calendar 10.14.11+ immediately.
• If upgrade delayed: disable plugin or apply WAF virtual patch, rate limiting, and CAPTCHA protections.
• Search logs for bookings-related enumeration or abnormal traffic and preserve evidence.
• Rotate keys and privileged credentials if you see signs of compromise.
• Notify affected parties if PII exposure is confirmed and comply with applicable laws.
• Implement long-term patching automation and monitoring.

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If you’d like help with any of the technical steps above — creating precise WAF rules for your environment, applying virtual patches, or auditing booking forms for PII — our team at WP-Firewall can assist. We specialize in protecting WordPress sites with practical, minimally disruptive controls so your site stays available while remaining secure.