CVE-2026-103877: Apache Software Foundation Apache Directory LDAP API

Critical severity, CVSS 9.8. EPSS: 0.6% chance of exploitation in the next 30 days.

Deserialization of Untrusted Data vulnerability in Apache Directory LDAP API. A rogue/compromised LDAP server (or pre-TLS MITM) can answer a client's loadSchema() subschema search with a schema object that contains a serialized Java class, allowing some potential RCE.  This issue affects Apache Directory LDAP API: from 2.1.0 before 2.1.9. Users are recommended to upgrade to version 2.1.9, which fixes the issue.

Affected products

• Apache Software Foundation Apache Directory LDAP API: from 2.1.0, before 2.1.9 (fixed in 2.1.9)

Published 2026-10-02. Last modified 2026-10-07.