CVE-2026-111727

medium

Description

The Appointment Booking Calendar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'vs_text_submitbtn' parameter in all versions up to, and including, 1.4.05 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the attacker to be assigned as a calendar owner, a per-user grant that any administrator can extend to users as low as Subscriber level through the plugin's calendar list screen. Exploitation by attackers with subscriber-level access and above requires that an administrator has assigned the attacker's account as owner (`conwer`) of a calendar via the plugin's calendar list screen; the plugin's UI lists all registered users regardless of role, so a Subscriber can be assigned. On a default installation, where that is not configured, the vulnerability requires attackers with editor-level access and above.

References

https://www.wordfence.com/threat-intel/vulnerabilities/id/dd0e4753-222a-421f-a830-58f6af055dd8?source=cve

https://plugins.trac.wordpress.org/log/appointment-booking-calendar/

https://plugins.trac.wordpress.org/changeset/3750835/appointment-booking-calendar/trunk/inc/cpabc_scheduler.inc.php

https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_scheduler.inc.php#L194

https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_on.inc.php#L398

https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_go.inc.php#L690

https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_go.inc.php#L616

https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.4.05/inc/cpabc_apps_go.inc.php#L102

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-111577

Details

Source: Mitre, NVD

Published: 2026-10-28

Updated: 2026-10-28

Risk Information

CVSS v2

Base Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 6.4

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Severity: Medium