Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style Sheets (CSS) @import directives in an HTML e-mail message.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:LI:LA:N7.2/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NInjection