CVE-2026-93636

Zimbra Collaboration Suite LDAP Filter Injection via Calendar Resource Attribute Name

Published Oct 23, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Description
An LDAP filter injection vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to query otherwise unreturned attributes of calendar resources through SearchCalendarResourcesRequest. Zimbra escapes search values but inserts the supplied attribute names directly into LDAP filter expressions without validation. An attacker can inject additional conditions and use repeated matching queries to recover readable resource attributes such as internal mailbox hostnames and mail transport routes. The search remains restricted to calendar-resource objects and the LDAP service account's access rights. ZCS 10.1.16 and 10.1.21 are affected.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Synacor
Synacor zimbra Collaboration Suite
CPEs cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*
Vendors & Products Synacor
Synacor zimbra Collaboration Suite
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Zimbra
Zimbra zimbra Collaboration Suite
Vendors & Products Zimbra
Zimbra zimbra Collaboration Suite
Type Values Removed Values Added
Description An LDAP filter injection vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to query otherwise unreturned attributes of calendar resources through SearchCalendarResourcesRequest. Zimbra escapes search values but inserts the supplied attribute names directly into LDAP filter expressions without validation. An attacker can inject additional conditions and use repeated matching queries to recover readable resource attributes such as internal mailbox hostnames and mail transport routes. The search remains restricted to calendar-resource objects and the LDAP service account's access rights. ZCS 10.1.16 and 10.1.21 are affected.
Title Zimbra Collaboration Suite LDAP Filter Injection via Calendar Resource Attribute Name
Weaknesses CWE-90
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
rapid7
Published
Updated
Oct 28, 2026, 7:50 PM
Reserved
Sep 18, 2026, 12:22 PM
Status
Analyzed
Published
Oct 23, 2026, 2:17 PM
Modified
Oct 28, 2026, 9:15 PM