OpenCATS before 0.10.0 Missing Authorization in Calendar editEvent/deleteEvent

Advisories

OpenCATS before 0.10.0 Missing Authorization in Calendar editEvent/deleteEvent

Severity: medium
Date: 10/20/2026
Affecting: OpenCATS >= 0, < 0.10.0
CVE: CVE-2026-113349
CWE: CWE-639 Authorization Bypass Through User-Controlled Key
CVSS: 5.3
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
References: https://github.com/opencats/OpenCATS/issues/720
https://github.com/opencats/OpenCATS/commit/aa3b414c3672f5010ca26c44192aa8e72d3735bd
OpenCATS v0.10.0 Release Notes
https://github.com/opencats/OpenCATS/blob/5781f41814f09493c7ce05b9251b5e09c1aff0cd/modules/calendar/CalendarUI.php#L555-L585
https://github.com/opencats/OpenCATS/blob/5781f41814f09493c7ce05b9251b5e09c1aff0cd/modules/calendar/CalendarUI.php#L690-L712
https://github.com/opencats/OpenCATS/blob/5781f41814f09493c7ce05b9251b5e09c1aff0cd/lib/Calendar.php#L83-L150
Credit: lighthousekeeper1212, leediay153 from Viettel Post
Description: OpenCATS before 0.10.0 contains a missing authorization vulnerability in CalendarUI::onEditEvent() and onDeleteEvent() that allows authenticated users to modify or delete other users' calendar events. Attackers with EDIT or DELETE access can supply arbitrary eventID values to alter or remove any user's events, including non-public ones restricted to their owner.

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