PT-2026-77175 · Mybb · Mybb

CVE-2026-45121

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Published

2026-08-18

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Updated

2026-08-18

CVSS v3.1

4.3

Medium

VectorAV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Name of the Vulnerable Software and Affected Versions MyBB versions prior to 1.8.40
Description The calendar module fails to consistently verify permissions when listing calendars. This allows authenticated users to view the titles of calendars that should be inaccessible. The issue occurs within the calendar-selection paths in the calendar.php file, which perform permission checks against an invalid calendar context before returning the titles.
Recommendations Update to version 1.8.40.

Exploit

Fix

Incorrect Authorization

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Weakness Enumeration

Related Identifiers

CVE-2026-45121
GHSA-R25V-7PCM-Q34P

Affected Products

Mybb