CVE-2026-103877

Apache Directory LDAP API: Unsafe loading of Java code from LDAP schema elements

Published Oct 2, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
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.

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
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important

Type Values Removed Values Added
First Time appeared Apache
Apache directory Ldap Api
Vendors & Products Apache
Apache directory Ldap Api
Type Values Removed Values Added
Description 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.
Title Apache Directory LDAP API: Unsafe loading of Java code from LDAP schema elements
Weaknesses CWE-502
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Oct 7, 2026, 10:07 PM
Reserved
Oct 1, 2026, 12:43 PM
Status
Deferred
Published
Oct 2, 2026, 10:17 AM
Modified
Oct 7, 2026, 11:16 PM
Severity
Important
Public date
Oct 2, 2026, 10:08 AM