8.7

CVE-2026-45116

MyBB: Profile field type confusion XSS

MyBB is free and open source forum software. Prior to 1.8.40, the user datahandler does not properly validate checkbox and multiselect profile field types, resulting in stored JavaScript code injection. UserDataHandler::verify_profile_fields() only performs the specialized validation when is_array($profile_fields[$field]) is true. A non-array profile_fields[fidX] value instead of the expected profile_fields[fidX][] shape falls through to generic text handling and is stored without verification. The affected value is then rendered directly by member.php and inc/functions_post.php rather than processed by the MyCode parser. The uniquely identifying implementation details include inc/datahandlers/user.php. This issue is fixed in version 1.8.40.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellermybb
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Produkt mybb
Version < 1.8.40
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.3% 0.228
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 8.7 2.3 5.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

https://github.com/mybb/mybb/releases/tag/mybb_1840
https://mybb.com/versions/1.8.40
https://github.com/mybb/mybb/security/advisories/GHSA-4p6g-p3qh-559v
https://github.com/mybb/mybb/commit/c32f0c22baab704a68b8d58fcdd2f26fadbbe19b