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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-45121 Detail

Description

MyBB is free and open source forum software. Prior to 1.8.40, the calendar module does not check permissions consistently when listing calendars, allowing authenticated users to access titles of calendars that are otherwise inaccessible. The affected calendar-selection paths in calendar.php perform permission checks against an invalid calendar context before returning calendar titles. The uniquely identifying implementation details include titles of inaccessible calendars, and invalid calendar permission context. This issue is fixed in version 1.8.40.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/mybb/mybb/commit/78e07fea34a6f6c326e668526bfb8e451c19e966 GitHub, Inc.
https://github.com/mybb/mybb/releases/tag/mybb_1840 GitHub, Inc.
https://github.com/mybb/mybb/security/advisories/GHSA-r25v-7pcm-q34p GitHub, Inc.
https://mybb.com/versions/1.8.40 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-863 Incorrect Authorization GitHub, Inc.  

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-45121
NVD Published Date:
08/18/2026
NVD Last Modified:
08/18/2026
Source:
GitHub, Inc.