In the Loofah gem through 2.2.0 for Ruby, non-whitelisted HTML attributes may occur in sanitized output by republishing a crafted HTML fragment.
Exploitability
AV:NAC:LPR:NUI:RScope
S:CImpact
C:LI:LA:N6.1/CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N