The vulnerability exists due to a security filtering flaw within the mail compliance validation engine, allowing authenticated email accounts to bypass active administrator configured external forwarding rules and exfiltrate mailbox data.
https://www.securityweek.com/zimbra-update-patches-critical-vulnerabilities/
https://thehackernews.com/2026/07/zimbra-patches-critical-snmp-command.html
Source: Mitre, NVD
Published: 2026-07-23
Base Score: 5.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N
Severity: Medium
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N