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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-352"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45128.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"fixed": "1.8.40"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
}
]
},
{
"extracted_events": [
{
"range": [
{
"fixed": "1.8.40"
},
{
"fixed": "1.8.40"
}
],
"source": "DESCRIPTION"
}
]
}
]
}{
"extracted_events": [
{
"range": [
{
"fixed": "736a2bcbc7cc104df8ae6c0a160aa3917a1ceec0"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "mybb_1840",
"range": [
{
"fixed": "e9942c6d19ac1709b3df7357cfb8810774c8d3ac"
}
],
"source": "REFERENCES_TAG"
}
]
}