Medium (5.4) in mybb mybb. EPSS 0.3% chance of exploitation in the next 30 days.
A stored cross-site scripting (XSS) vulnerability in the component install\index.php of MyBB v1.8.38 allows attackers to execute arbitrary web scripts or HTML via a crafted payload injected into the Website Name parameter. NOTE: this is disputed by the Supplier because Website Name can only be set by an administrator, who may use JavaScript if they wish.
Severity
CVSS 3.1
5.4 medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EPSS
0.3% chance of exploitation in the next 30 days; higher than 19% of CVEs (scores of 2026-10-31)