CVE-2026-93647

critical

Description

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.

References

https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-87102

Details

Source: Mitre, NVD

Published: 2026-09-25

Updated: 2026-09-29

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Severity: Critical

EPSS

EPSS: 0.00229