CVE-2026-93647
An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.
- Published Sep 25, 2026
- CVSS 9.3 critical
- 0.2% chance of exploitation in the next 30 days (EPSS)