CVE-2026-45126

LOW 3.5

MyBB: ACP Questions state CSRF

CVSS Score

3.5

EPSS Score

0.0%

EPSS Percentile

0th

MyBB is free and open source forum software. Prior to 1.8.40, the Admin CP Security Questions module does not validate the anti-CSRF token correctly, allowing same-site attackers to enable or disable registration challenge questions with a specially crafted URL. The controller processes GET requests for the disable and enable actions to modify mybb_questions.active without verifying the my_post_key token attached by the user interface. The uniquely identifying implementation details include admin/modules/config/questions.php. This issue is fixed in version 1.8.40.

CWE	CWE-352
Vendor	mybb
Product	mybb
Published	Aug 18, 2026
Last Updated	Aug 18, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Affected Versions

mybb / mybb

< 1.8.40

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/mybb/mybb/security/advisories/GHSA-m42q-vgx3-fqcc github.com: https://github.com/mybb/mybb/commit/6893b395c7fa3b9e4de6235caea0ce198c376c4f github.com: https://github.com/mybb/mybb/releases/tag/mybb_1840 mybb.com: https://mybb.com/versions/1.8.40