CVE-2026-93628

The record

An attendee authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to forge another attendee's response to an existing meeting. Zimbra passes a null sender identity when processing iCalendar REPLY components, causing the attendee authorization filter to be skipped. An attacker who knows the meeting UID, organizer address and attendee address can send a non-outdated reply that changes the attendee's participation status in the organizer's calendar. The change occurs automatically during delivery without organizer or attendee interaction. ZCS 10.1.16 and 10.1.21 are affected.

Affected packages

Related vulnerabilities

• CVE-2026-63115 ActivityPub is a multi-tenant ActivityPub server for Ghost, built with Fedify. CWE-290
• CVE-2026-104623 A security vulnerability exists in the authorization handling for the local (management)… CWE-290
• CVE-2026-119703 xiaozhi-esp32-server through 0.9.8 contains an authentication bypass vulnerability in… CWE-290
• CVE-2026-104615 A security vulnerability was discovered in SUSE Rancher Fleet's cluster registration… CWE-290
• CVE-2026-91914 Dell OpenManage Enterprise, versions prior to 4.8.0, contains an Authentication Bypass by… CWE-290
• CVE-2026-119425 OPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in… CWE-290
• CVE-2026-115962 Authentication Bypass by Spoofing vulnerability in myCred myCred mycred allows Identity… CWE-290
• CVE-2026-118653 Echo is a Go web framework. CWE-290