CVE-2026-45128

EUVD-2026-61050

18.08.2026, 16:17

MyBB is free and open source forum software. Prior to 1.8.40, the ACP Users View Manager module does not validate requests correctly, allowing same-site attackers to change a victim administrator's default user list view by embedding a specially crafted URL. The Set as Default control named set_default in Admin CP, Users & Groups, Users, View Manager changes the administrator's default view on GET requests without request forgery protection. The uniquely identifying implementation details include Users & Groups → Users → View Manager, and admin/inc/functions_view_manager.php. This issue is fixed in version 1.8.40.

CSRF

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
GitHub_M	CNA	3.5 LOW	NETWORK	LOW	LOW	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
mybb	mybb	𝑥 < 1.8.40	CNA

Common Weakness Enumeration

CWE-352 - Cross-Site Request Forgery (CSRF)
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.

References

https://github.com/mybb/mybb/commit/736a2bcbc7cc104df8ae6c0a160aa3917a1ceec0

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

https://github.com/mybb/mybb/security/advisories/GHSA-m6hr-25cj-p58q

https://mybb.com/versions/1.8.40