Description
Memory allocation with excessive size value vulnerability in Apache Directory LDAP API.



A malicious peer (or a MITM) can send a small BER-encoded response causing a large memory allocation before any data is received. This can lead to an OutOfMemoryError and denial of service.



The client JVM OOMs (OutOfMemoryError bypasses the DecoderException handlers) or pins the large allocation per connection while the attacker stalls.



A handful of connections exhausts any heap. The same bytes from an unauthenticated pre-bind client hit any embedding server that did not set MAX_PDU_SIZE_ATTR.



This issue affects Apache Directory LDAP API: from 1.2.0 before 1.2.9.



Users are recommended to upgrade to version 1.2.9, which fixes the issue.
Published: 2026-10-02
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Mon, 05 Oct 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Sat, 03 Oct 2026 00:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important


Fri, 02 Oct 2026 22:30:00 +0000

Type Values Removed Values Added
References

Fri, 02 Oct 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache directory Ldap Api
Vendors & Products Apache
Apache directory Ldap Api

Fri, 02 Oct 2026 09:30:00 +0000

Type Values Removed Values Added
Description Memory allocation with excessive size value vulnerability in Apache Directory LDAP API. A malicious peer (or a MITM) can send a small BER-encoded response causing a large memory allocation before any data is received. This can lead to an OutOfMemoryError and denial of service. The client JVM OOMs (OutOfMemoryError bypasses the DecoderException handlers) or pins the large allocation per connection while the attacker stalls. A handful of connections exhausts any heap. The same bytes from an unauthenticated pre-bind client hit any embedding server that did not set MAX_PDU_SIZE_ATTR. This issue affects Apache Directory LDAP API: from 1.2.0 before 1.2.9. Users are recommended to upgrade to version 1.2.9, which fixes the issue.
Title Apache Directory LDAP API: Denial of service via excessive memory allocation in BER decode
Weaknesses CWE-789
References

Subscriptions

Apache Directory Ldap Api
cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-10-05T18:10:33.132Z

Reserved: 2026-09-29T16:17:56.332Z

Link: CVE-2026-102731

cve-icon Vulnrichment

Updated: 2026-10-02T21:07:18.741Z

cve-icon NVD

Status : Deferred

Published: 2026-10-02T10:17:04.530

Modified: 2026-10-05T19:17:12.740

Link: CVE-2026-102731

cve-icon Redhat

Severity : Important

Publid Date: 2026-10-02T09:22:00Z

Links: CVE-2026-102731 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-03T01:30:18Z

Weaknesses