Vulnerability · Published Oct 23, 2026 · Assigned by rapid7
CVE-2026-93636Zimbra Collaboration Suite LDAP Filter Injection via Calendar Resource Attribute Name
Medium 4.3
In plain English
A medium-severity security flaw in Zimbra Collaboration Suite from Zimbra. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Zimbra | Zimbra Collaboration Suite | 0 – through 10.1.21 |
Weakness: CWE-90 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N