An interesting fact: in the CISA KEV, we can find six (6) 0-day XSS vulnerabilities. All but one are related to e-mail products.
1. CVE-2025-27915, Zimbra
2. CVE-2024-11182, MDaemon
3. CVE-2023-37580, Zimbra
4. CVE-2023-5631, Roundcube
5. CVE-2022-24682, Zimbra
6. CVE-2021-1879, Apple
4 days ago