Permission Bypass Vulnerability in MyBB Forum Software
CVE-2026-45124

4.3MEDIUM

Key Information:

Vendor

Mybb

Status
Mybb
Vendor
CVE Published:
18 August 2026

What is CVE-2026-45124?

MyBB forum software prior to version 1.8.40 contains a vulnerability where the Mod CP Report Center fails to consistently check user permissions. This allows moderators without the necessary report-management permissions to mark reports as resolved. Specifically, the modcp.php?action=do_reports handler can be accessed even without the capabilities to manage reported content or posts. As a result, if there are no forums specified, the $flist_reports is empty, leading to the execution of the UPDATE mybb_reportedcontent query without the expected permission checks. This flaw poses a significant risk of unauthorized actions being performed within the forum. The issue has been addressed in version 1.8.40, so users are encouraged to upgrade as soon as possible. For more details, please refer to the official advisories and release notes.

Affected Version(s)

mybb < 1.8.40

References

https://github.com/mybb/mybb/security/advisories/GHSA-gfx...
x_refsource_CONFIRM
https://github.com/mybb/mybb/commit/5cda5f6d183bc2cac24f0...
x_refsource_MISC
https://github.com/mybb/mybb/releases/tag/mybb_1840
x_refsource_MISC

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.