GemBooking <= 1.7.0 - Unauthenticated Team Member Double-Booking
Strategic Overview
- Status
- Patched in 1.7.1
- Affected Version
<= 1.7.0- CVSS
- 5.3Medium
- Weakness type
- CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization
- CVE
CVE-2026-123128
At a glance
CVE-2026-123128 is a medium-severity Concurrent Execution using Shared Resource with Improper Synchronization vulnerability in the GemBooking WordPress plugin, affecting versions <= 1.7.0. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.7.1; sites on affected versions should update now. Disclosed November 2026, reported by Khalid Mostafa Ismail.
Vulnerability Overview
The GemBooking plugin for WordPress is vulnerable to Race Condition in all versions up to, and including, 1.7.0. This is due to a booking advisory lock scoped only to the bookable object_id, allowing concurrent requests on different bookables to race on shared team members, resources, or hosts without serialisation. This makes it possible for unauthenticated attackers to create overlapping confirmed bookings for the same team member by sending simultaneous booking requests against different bookable items, bypassing availability checks.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
Remediation
Update to version 1.7.1, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: GemBooking 1.7.1 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in GemBooking – Appointment Booking, Booking Calendar & Reservations
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