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.
References7
- github.com/opencats/OpenCATS/blob/5781f41814f09493c7ce05b9251b5…
- github.com/opencats/OpenCATS/blob/5781f41814f09493c7ce05b9251b5…
- github.com/opencats/OpenCATS/blob/5781f41814f09493c7ce05b9251b5…
- github.com/opencats/OpenCATS/commit/aa3b414c3672f5010ca26c44192…
- github.com/opencats/OpenCATS/issues/720
- github.com/opencats/OpenCATS/releases/tag/v0.10.0
- www.vulncheck.com/advisories/opencats-before-0.10.0-missing-aut…
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - CVSS 4.0
-
5.3
MEDIUM
Score source: CNA
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 18 · as of 9 November 2026
- CWE
- CWE-639
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.