Broken access control in “Simple Bike Rental” (≤ 1.0.6) — what site owners must know

By a Hong Kong security expert — concise advisory for site operators and developers. Last updated: 2025-12-12

TL;DR

A broken access control vulnerability was reported in the WordPress plugin Simple Bike Rental (versions ≤ 1.0.6). An authenticated user with the Subscriber role (or higher) could access booking information that should have been restricted. The issue is tracked as CVE‑2025‑14065 and fixed in version 1.0.7.

Impact is rated low overall (CVSS 5.3) because the attacker needs a Subscriber-level account. Still, booking records commonly include personally identifiable information (PII) — names, contact details, dates/times — so leakage poses privacy and compliance risk.

If you run sites with this plugin: update to Simple Bike Rental 1.0.7 or later immediately. If you cannot update right away, follow the mitigations below (role hardening, virtual patching via a WAF, monitoring).

This advisory explains the vulnerability in practical terms, likely impacts, indicators of compromise, and a response plan for site owners and developers.

About this post

This advisory is written from the perspective of an independent Hong Kong security practitioner. The goal is practical guidance for administrators and developers: clear, actionable steps to reduce exposure without publishing exploit techniques that would aid attackers.

What happened: summary of the vulnerability

• Software: Simple Bike Rental (WordPress plugin)
• Affected versions: ≤ 1.0.6
• Fixed in: 1.0.7
• Vulnerability: Broken Access Control (missing authorization check)
• Required access: Authenticated Subscriber (or higher)
• CVE: CVE‑2025‑14065
• Severity: Low (CVSS 5.3)
• Reporter: Athiwat Tiprasaharn (Jitlada)

In short: an endpoint in the plugin that returns booking data did not perform ownership/capability checks. Any logged-in user with Subscriber privileges could request booking records belonging to other users. The plugin author released a patch in 1.0.7 that adds the missing checks.

Why this matters: risks for site owners

Even with a low severity rating, real risk exists because:

• Many WordPress sites permit public registration or assign Subscriber accounts as part of flows; attackers can create accounts and abuse access.
• Booking data typically contains PII (names, phone numbers, emails), timestamps, locations, and sometimes payment references. Exposure can trigger privacy obligations and reputational harm.
• Attackers can create many Subscriber accounts to scrape bookings at scale.
• Exposed internal identifiers may be useful to attackers for pivoting to other systems (support portals, CRM, order management).

Even low-severity issues become high-impact when abused at scale. Prompt patching and compensating controls are therefore important.

Technical overview (non-exploitative)

The issue is a classic broken access control:

• An endpoint (AJAX action or REST route) returned booking records.
• The code checked that a user was logged in but did not verify ownership or required capability.
• Consequently, any authenticated user could retrieve other users’ bookings.

Common coding mistakes that lead to this:

• Using is_user_logged_in() alone instead of capability checks or ownership checks.
• Exposing admin-only functions via public AJAX/REST actions without current_user_can() or equivalent checks.
• Relying on UI obscurity (hidden links) rather than server-side checks.
• Omitting nonce verification for actions that should be protected.

Correct patterns include:

• Use fine-grained capability checks (e.g., current_user_can()) or custom capabilities.
• For per-object access, compare the current user’s ID to the booking’s owner ID before returning data.
• For REST endpoints, implement permission_callback so unauthorized users are blocked before the callback executes.
• Verify nonces on AJAX requests where appropriate.

Example safe patterns (illustrative)

These examples show the intended approach for authorization checks (do not copy blindly — adapt to your plugin structure and security policy):

<?php
// Example pattern (adapt to your code)
if ( ! is_user_logged_in() ) {
    wp_send_json_error( 'login_required', 401 );
}
$current_user_id = get_current_user_id();

// If the booking belongs to the current user
if ( $booking->user_id !== $current_user_id && ! current_user_can( 'manage_options' ) ) {
    wp_send_json_error( 'forbidden', 403 );
}

// proceed to return booking data safely
?>

<?php
register_rest_route( 'sbr/v1', '/booking/(?P<id>\d+)', array(
    'methods'  => 'GET',
    'callback' => 'sbr_get_booking',
    'permission_callback' => function( $request ) {
        $user = wp_get_current_user();
        if ( ! $user || 0 === $user->ID ) {
            return new WP_Error( 'rest_not_logged_in', 'You must be logged in', array( 'status' => 401 ) );
        }
        // Additional ownership/capability checks here...
        return true;
    }
) );
?>

Exploitability: how easy is it?

• The attacker must be authenticated (Subscriber or higher). If your site allows public registration, creating accounts is trivial.
• If your site disables public registration and Subscriber accounts are not issued, risk is much lower.
• An accessible endpoint that leaks data enables automated scraping. Attackers can create many accounts and collect records at scale.

Exploitability ranges from “easy” to “moderate” depending on site registration policy and monitoring controls.

Immediate actions for site owners (0–24 hours)

1. Update the plugin to 1.0.7 or later immediately. This is the most important step — the vendor fixed the missing authorization checks.
2. If you cannot update immediately, disable or remove the plugin. If the plugin is non‑essential, take it offline until patched.
3. Harden user registration and Subscriber flows:
   • Disable public registration if unnecessary (Settings → General → Membership).
   • If registrations are required, enable email verification and consider manual approval.
   • Reduce default privileges for new accounts and avoid granting booking access to raw Subscribers.
4. Review logs for anomalies:
   • Search for repeated requests to plugin endpoints and unexpected GETs for booking data.
   • Look for bursts of account creation followed by booking endpoint access (scraping patterns).
5. If you detect confirmed data exposure, treat exposed PII as compromised: notify affected users as required by law and revalidate/rotate any credentials or tokens linked to booking systems.
6. Consider applying temporary WAF rules or virtual patches where available:
   • Block unauthorised access to booking endpoints.
   • Rate-limit requests to slow or stop automated scraping.

Medium-term actions (24 hours to 2 weeks)

• Enforce least privilege across your site. Audit roles and remove unnecessary capabilities from Subscriber-level accounts.
• Add monitoring and alerting for repeated access to booking resources.
• Require stronger verification for accounts tied to bookings (email+phone verification, payment confirmation, or manual review).
• Log sensitive-data access with sufficient retention to support incident investigation.
• Review any custom hooks or third‑party integrations that touch the booking plugin for similar access-control mistakes.

How a WAF or security service can help (and what it cannot do)

A Web Application Firewall (WAF) or managed security service can provide important compensating controls but does not replace a code-level fix.

What a WAF/security service can do:

• Apply virtual patches (block/filter requests to specific endpoints or parameters).
• Rate-limit and throttle requests per user or IP to slow scraping.
• Block suspicious account creation patterns and flag anomalous authenticated-user behavior.
• Provide alerts for abnormal traffic patterns and centralised logging to support investigation.

What it cannot do:

• Fix missing authorization checks in the application code — the root cause remains until the plugin is patched.
• Completely prevent abuse by legitimate accounts whose credentials have been compromised, though it can help detect anomalies.

Detection: indicators to look for

• Requests to plugin-specific endpoints or AJAX actions that return booking data.
• High-volume GET/POST patterns for those endpoints.
• Multiple Subscriber accounts requesting bookings that are not their own.
• Same IP range creating accounts then immediately accessing booking endpoints.
• Requests missing expected CSRF/nonce tokens (if the plugin normally required them).

If you detect suspicious activity: export and preserve logs (web server, application, and WAF), identify involved accounts and suspend them temporarily, and notify affected users if PII was disclosed according to local legal obligations.

Remediation checklist for developers and site owners

For plugin developers (best-practice checklist)

• Implement capability checks in all endpoints (use current_user_can() or appropriate custom capabilities).
• For object-level permissions, check ownership (compare get_current_user_id() to the object owner).
• For REST API, implement permission_callback to avoid running callback logic for unauthorized users.
• Verify nonces for state-changing actions and consider them for sensitive reads where appropriate.
• Write unit and integration tests for access control paths (authorized, unauthorized, edge cases).
• Log access to sensitive resources for auditing.

For site owners/operators

• Patch plugins promptly when updates are released.
• Use least-privilege role configuration and review default user roles.
• Deploy WAF rules or virtual patches where feasible to reduce immediate exposure.
• Monitor for anomalous activity and maintain an incident response playbook.

Incident response: if you were compromised

1. Contain:
   • Disable the vulnerable plugin or update to 1.0.7 immediately.
   • Suspend suspicious user accounts and block suspicious IPs.
2. Investigate:
   • Gather server, plugin, and WAF logs spanning the period of concern.
   • Identify accessed data and affected accounts.
   • Preserve evidence — export logs offsite if needed for forensics.
3. Remediate:
   • Patch the plugin (1.0.7+).
   • Rotate secrets, API keys, or tokens that may have been exposed.
   • Force password resets for affected accounts if necessary.
4. Notify:
   • Inform affected users with accurate information about what was exposed and what you did.
   • Follow legal notification requirements in your jurisdiction (e.g., Hong Kong PDPO, EU GDPR, etc.).
5. Learn:
   • Perform root cause analysis: missing check or flawed endpoint design?
   • Improve development practices and add automated tests for access control.

Why timely updates are the single most effective defense

Updates fix known issues. Attackers scan for sites running vulnerable plugin versions, and the window between disclosure and mass scanning is short. Updating removes the vulnerability from your site (assuming the patch is correctly implemented).

If managing many sites, use staged automated updates with a rollback plan and testing process. Prioritise security patches for plugins that handle PII, payments, or user data.

For developers: avoid authoring “soft” protections

Weak patterns that give a false sense of security:

• Hiding links or UI elements with CSS/JS and assuming obscurity prevents access.
• Relying on nonces only for state changes while allowing GET requests to reveal sensitive data.
• Doing access checks in templates but not in endpoints serving JSON/REST — attackers can bypass the UI and call endpoints directly.

Always implement server-side authorization checks in the handler logic.

Long term: security hygiene and development culture

• Embed security reviews in the release process. Any change that touches endpoints should have an access-control review.
• Use automated checks (static analysis, dependency checks) and runtime monitoring.
• Educate development teams about role-based access control and the pitfalls of client-side protections.
• Maintain an inventory of installed plugins and prioritise updates for those that handle sensitive data.

Final checklist (quick)

• Update Simple Bike Rental to 1.0.7 or later now.
• If you cannot update immediately, disable the plugin or apply temporary WAF/virtual-patch controls.
• If you allow public registration: tighten verification and harden newly created Subscriber accounts.
• Monitor logs for scraping and unusual booking-access patterns.
• Have an incident response plan and be ready to notify affected users if PII is exposed.

Closing thoughts

Broken access control is common and often subtle. Even low-severity findings can cause meaningful privacy exposure when exploited at scale. The fix for Simple Bike Rental is available in 1.0.7 — patching is the top priority. Pair patching with short-term compensating controls (role hardening, WAF rules, monitoring) to reduce risk while you remediate.

Acknowledgements

The issue was responsibly disclosed by Athiwat Tiprasaharn (Jitlada). The CVE identifier is CVE‑2025‑14065.

If you want a tailored remediation checklist for your site (IPs to block, audit queries to run, or suggested WAF rules), reply with basic details about your WordPress environment (hosted vs self-hosted, whether registration is public, and whether you use the REST API for bookings) and a concise plan will be prepared.