CVE-2026-105257 Overview
CVE-2026-105257 affects the Appointment Booking Plugin for WordPress in versions before 5.7.5. The plugin fails to verify that an authenticated agent-level user is assigned to a customer before returning or searching that customer's record. Any authenticated agent can read and enumerate personal information for every customer on the site, including records managed by other agents. The weakness is classified as Authorization Bypass Through User-Controlled Key [CWE-639], a form of Insecure Direct Object Reference (IDOR).
Critical Impact
Authenticated agent-level accounts can harvest the personal data of all customers stored by the plugin, bypassing per-agent record isolation.
Affected Products
- Appointment Booking Plugin for WordPress versions prior to 5.7.5
- WordPress sites exposing agent-level accounts to the booking plugin
- Deployments relying on per-agent customer segregation for privacy compliance
Discovery Timeline
- 2026-10-21 - CVE-2026-105257 published to NVD
- 2026-10-21 - Last updated in NVD database
Technical Details for CVE-2026-105257
Vulnerability Analysis
The Appointment Booking Plugin exposes customer records to agent-level users through endpoints that return or search customer data. The plugin authenticates the agent and confirms the agent role, but it does not evaluate whether the requested customer is assigned to the calling agent. The access decision therefore relies only on authentication, not on an ownership check tied to the record identifier.
An agent can request arbitrary customer IDs or submit broad search queries. The server responds with records belonging to other agents, including personally identifiable information (PII) stored during the booking workflow. The flaw is a direct expression of [CWE-639] where the user-controlled customer identifier serves as the sole key to the record.
Exploitation requires valid agent credentials, so the attacker must already hold a legitimate low-privilege role on the site. No user interaction is needed and the attack is reachable over the network through standard plugin endpoints.
Root Cause
The plugin's record lookup and search handlers omit an authorization check that binds the customer record to the agent assignment. Role membership is treated as sufficient for access to the full customer dataset, rather than scoping queries to records owned by the requesting agent.
Attack Vector
An authenticated agent sends crafted requests to the plugin's customer retrieval or search endpoints with identifiers or search terms belonging to other agents. The server returns the matching records without verifying assignment. See the WPScan Vulnerability Report for additional technical context. No verified public exploit code is available at this time.
Detection Methods for CVE-2026-105257
Indicators of Compromise
- Agent accounts issuing high volumes of customer lookup or search requests to the booking plugin
- Sequential or enumerated customer identifiers appearing in access logs from a single agent session
- Broad or wildcard search parameters submitted to customer search endpoints by agent roles
Detection Strategies
- Review WordPress and web server access logs for agent accounts accessing customer IDs outside their assigned set
- Alert on bulk retrieval patterns against the Appointment Booking Plugin REST or admin-ajax endpoints
- Compare queried customer identifiers against the plugin's agent-to-customer assignment table to flag mismatches
Monitoring Recommendations
- Enable verbose logging on the Appointment Booking Plugin endpoints handling customer records
- Forward WordPress audit logs to a centralized analytics platform for behavioral baselining of agent activity
- Track the volume and diversity of customer records touched per agent session and alert on outliers
How to Mitigate CVE-2026-105257
Immediate Actions Required
- Upgrade the Appointment Booking Plugin to version 5.7.5 or later on all WordPress sites
- Audit existing agent accounts and revoke access for any accounts that are inactive or unnecessary
- Review access logs since the plugin was installed to identify prior enumeration of customer records
Patch Information
The vendor addressed the issue in Appointment Booking Plugin version 5.7.5. The fix enforces an assignment check so that agents can only read or search customers linked to their account. Refer to the WPScan Vulnerability Report for the fixed version reference.
Workarounds
- Restrict the agent role to trusted staff only until the plugin is updated
- Temporarily disable the Appointment Booking Plugin on sites that cannot update immediately
- Place the WordPress admin and plugin endpoints behind an IP allowlist or VPN to reduce exposure of agent sessions
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
