CVE-2026-15254 Overview
CVE-2026-15254 affects the Simply Schedule Appointments WordPress plugin in versions before 1.6.12.11. The plugin exposes an administrative appointment-listing shortcode without a capability check, and its per-user result scoping fails open for non-staff users. Any authenticated user with the Contributor role or higher can render the shortcode and enumerate every customer appointment stored by the site. Disclosed records include customer names, email addresses, phone numbers, and free-form appointment notes. The issue is categorized as broken authorization [CWE-863].
Critical Impact
Contributor-level accounts can read all customer appointment records site-wide, exposing personally identifiable information (PII) that supports downstream phishing, fraud, and privacy-regulation violations.
Affected Products
- Simply Schedule Appointments WordPress plugin versions prior to 1.6.12.11
- WordPress installations that allow Contributor or higher self-registration or delegated authoring
- Sites embedding the plugin's administrative appointment-listing shortcode in front-end content
Discovery Timeline
- 2026-08-03 - CVE-2026-15254 published to the National Vulnerability Database
- 2026-08-03 - Last updated in NVD database
Technical Details for CVE-2026-15254
Vulnerability Analysis
Simply Schedule Appointments registers a shortcode intended for administrative appointment listing. The shortcode handler renders appointment records but omits a current_user_can() capability check before executing its query. A secondary scoping routine attempts to restrict output to the requesting user's own appointments when the caller is a staff member. For accounts that do not map to a staff role, the scoping predicate is not applied, and the query returns all appointment rows for the site.
Exploitation requires only a low-privilege authenticated session. A Contributor can create or edit a post containing the shortcode and preview or publish it to trigger server-side rendering. The rendered output includes each appointment's customer name, email address, phone number, and notes field. The vulnerability is a confidentiality issue and does not modify data or affect availability.
Root Cause
The root cause is broken authorization [CWE-863]. Two independent controls fail in combination: the shortcode omits a capability gate, and the per-user filter defaults to unrestricted results when the caller lacks a staff role. Fail-open logic in the scoping branch converts a missing role into full disclosure rather than denial.
Attack Vector
An attacker authenticates as any user with Contributor privileges or higher. The attacker inserts the plugin's administrative appointment-listing shortcode into post or page content they are permitted to edit. Rendering the content, including via the WordPress preview endpoint, returns the full appointment dataset in the HTML response. No user interaction from an administrator is required.
See the WPScan Vulnerability Report for the vendor-coordinated technical write-up.
Detection Methods for CVE-2026-15254
Indicators of Compromise
- Post or page revisions authored by Contributor or Author accounts that contain the Simply Schedule Appointments administrative shortcode.
- WordPress preview or draft rendering requests (preview=true, p=<id>) initiated by non-administrator users immediately after shortcode insertion.
- Outbound scraping patterns where a low-privilege account repeatedly loads its own draft posts.
Detection Strategies
- Audit the wp_posts table for shortcode tags associated with the plugin embedded by users below the Editor role.
- Correlate WordPress authentication logs with post-edit and preview events to surface Contributor accounts accessing appointment content.
- Compare plugin version metadata in wp_options against the fixed release 1.6.12.11 across the WordPress estate.
Monitoring Recommendations
- Enable WordPress activity logging that captures shortcode insertions, post previews, and role assignments.
- Alert on new Contributor or Author account creation on sites that host the plugin.
- Monitor HTTP responses from post-preview endpoints for markers matching appointment table structures such as customer email columns.
How to Mitigate CVE-2026-15254
Immediate Actions Required
- Update the Simply Schedule Appointments plugin to version 1.6.12.11 or later on all WordPress sites.
- Review Contributor, Author, and custom low-privilege roles and remove accounts that are not actively required.
- Rotate exposed customer contact data handling procedures and notify affected data subjects if disclosure is confirmed under applicable privacy regulations.
Patch Information
The vendor addressed the issue in Simply Schedule Appointments 1.6.12.11 by adding a capability check to the administrative shortcode handler and correcting the per-user scoping logic so that non-staff callers are denied rather than granted unrestricted access. Refer to the WPScan Vulnerability Report for coordinated disclosure details.
Workarounds
- Disable the Simply Schedule Appointments plugin until the site is upgraded to 1.6.12.11 or later.
- Restrict post and page editing capabilities so that only trusted Editor and Administrator accounts can insert shortcodes.
- Use a web application firewall rule to block requests whose rendered content contains the vulnerable shortcode when submitted by non-administrator users.
# Example WP-CLI commands to inventory and update affected sites
wp plugin get simply-schedule-appointments --field=version
wp plugin update simply-schedule-appointments --version=1.6.12.11
wp user list --role=contributor --fields=ID,user_login,user_registered
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
