CVE-2026-45128 | BDVDB-2026-360840 Detail

mybbmybb

Description#

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.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact low, availability impact none. Attack vector: network.

Weaknesses#

CWE-352 Cross-Site Request Forgery (CSRF)

References#

Exploit#

No public exploit known

History#

Version 12026-08-18Record published in the CVE List.

Published

Published: 2026-08-18
Last modified: 2026-08-18

Vendor information

Vendor: mybb
Product: mybb

All mybb vulnerabilities

Score

3.5 Low

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 6.9.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Cross-Site Request Forgery

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
< 1.8.40
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

3.5 Low

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	Low
User Interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity	Low
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).