CVE-2026-93636 Zimbra Collaboration Suite LDAP Filter Injection via Calendar Resource Attribute Name

Medium 4.3 Published 23 Oct 2026 Updated 28 Oct 2026

Exploited in the wild: Not known
Fix: None listed

What is CVE-2026-93636?

CVE-2026-93636 is a medium-severity vulnerability in Synacor Zimbra Collaboration Suite, published on 23 Oct 2026.

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.

Weakness: CWE-90

Which versions are affected by CVE-2026-93636?

It affects 1 product.

Products include Synacor Zimbra Collaboration Suite.

How do I fix CVE-2026-93636?

No fix has been published for CVE-2026-93636 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-93636 being exploited?

There is no known exploitation of CVE-2026-93636 in the wild and no public exploit code.

All Synacor Zimbra Collaboration Suite vulnerabilities

Sources

Also known as GHSA-xmgq-97vm-wxrh.