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Vulnerabilities / CVE-2026-93627

CVE-2026-93627

Published 2026-10-23 · published (not yet in NVD)

CVE-2026-93627

Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar CANCEL/REQUEST Organizer

5.3 MEDIUM
CVSS 3.1 · CNA
0.3%
chance of exploitation in the next 30 days (EPSS; higher than 19% of CVEs)

An organizer authentication vulnerability in the email calendar processing of Zimbra Collaboration Suite (ZCS) allows an unauthenticated sender to cancel or modify an existing meeting in a recipient's calendar. Zimbra accepts iCalendar CANCEL and REQUEST components without verifying that the email sender is authorized to act as the supplied organizer. An attacker who knows the meeting UID and organizer address can supply a non-outdated sequence number to move the recipient's meeting to Trash or replace its details. Processing occurs automatically during email delivery without recipient interaction. ZCS 10.1.16 and 10.1.21 are affected.

Scores

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NCNA

Affected products

  • Zimbra Zimbra Collaboration Suite: 0 to ≤ 10.1.21

Weakness: CWE-290

2 references (advisories, patches, write-ups)

Sources: CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.

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