Vulnerability record · CVE-2026-89063 · published 16 September 2026
CVE-2026-89063: Insecure direct object reference vulnerability
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 28.1 via the 'conversation_id' parameter due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to read the full AI booking conversation transcript of any customer — leaking names, email addresses, phone numbers, and appointment details echoed by the assistant — and inject arbitrary messages into any victim conversation that are subsequently replayed to the Cloud AI worker along with the full private history. Because AI conversations are stored with no owner, user, or session identifier and conversation IDs are sequential integers, an unauthenticated attacker can enumerate all customer conversations simply by incrementing the conversation_id parameter.
Description
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 28.1 via the 'conversation_id' parameter due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to read the full AI booking conversation transcript of any customer — leaking names, email addresses, phone numbers, and appointment details echoed by the assistant — and inject arbitrary messages into any victim conversation that are subsequently replayed to the Cloud AI worker along with the full private history. Because AI conversations are stored with no owner, user, or session identifier and conversation IDs are sequential integers, an unauthenticated attacker can enumerate all customer conversations simply by incrementing the conversation_id parameter.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-89063), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.
