What is CVE-2026-93636?

CVE-2026-93636 is a medium-severity vulnerability in Zimbra Collaboration Suite, classified under LDAP Injection. CVSS score: 4.3/10. Published 2026-10-23.

How severe is CVE-2026-93636?

Medium severity. CVSS v3 base score is 4.3 out of 10.

LDAP Injection in Zimbra Collaboration Suite

CVE-2026-93636

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.

Published 2026-10-23 · last modified 2026-10-23.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Zimbra Collaboration Suite

Weakness classification (CWE)

CWE-90 — LDAP Injection

References

wiki.zimbra.com/wiki/Zimbra_Security_Advisories (vendor-advisory)
www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ (related)

Frequently asked questions

What is CVE-2026-93636?: CVE-2026-93636 is a medium-severity vulnerability in Zimbra Collaboration Suite, classified under LDAP Injection. CVSS score: 4.3/10. Published 2026-10-23.
How severe is CVE-2026-93636?: Medium severity. CVSS v3 base score is 4.3 out of 10.