CVE-2026-45120

medium

Description

MyBB is free and open source forum software. Prior to 1.8.40, the calendar module does not verify private event status consistently, allowing users with viewing and moderation permissions to access and moderate private events. The private-event check used by get_events() in inc/functions_calendar.php and the event action is missing from the remaining calendar.php actions, despite the limited-access behavior described in inc/languages/english/calendar.lang.php. This issue is fixed in version 1.8.40.

References

https://mybb.com/versions/1.8.40

https://github.com/mybb/mybb/security/advisories/GHSA-c2hm-g9w6-pv6x

https://github.com/mybb/mybb/releases/tag/mybb_1840

https://github.com/mybb/mybb/commit/c077e6c29755187c4df78a1e674dd61bc55701b3

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-61017

Details

Source: Mitre, NVD

Published: 2026-08-18

Updated: 2026-09-08

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: 5.4

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

Severity: Medium

EPSS

EPSS: 0.00304