CVE-2026-102731: CWE-789 Memory allocation with excessive size value in Apache Software Foundation Apache Directory LDAP API
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.
AI Analysis
Technical Summary
This vulnerability involves improper handling of BER-encoded LDAP responses in Apache Directory LDAP API. An attacker can send a small but maliciously crafted response that causes the client to allocate an excessively large amount of memory prematurely. This can result in an OutOfMemoryError that bypasses normal exception handling or cause the client to pin large memory allocations per connection, effectively exhausting the JVM heap and causing denial of service. The flaw affects versions from 1.2.0 up to but excluding 1.2.9. The vulnerability is addressed by upgrading to version 1.2.9.
Potential Impact
Exploitation of this vulnerability can lead to denial of service on the client side by exhausting JVM heap memory. This can disrupt normal operation of applications using the affected LDAP API. There is no indication of remote code execution or data compromise. The denial of service can be triggered by unauthenticated attackers sending crafted LDAP responses, including man-in-the-middle scenarios.
Mitigation Recommendations
Users should upgrade Apache Directory LDAP API to version 1.2.9 or later, which contains the fix for this vulnerability. No other mitigations or workarounds are specified. Applying the official fix fully addresses the issue.
CVE-2026-102731: CWE-789 Memory allocation with excessive size value in Apache Software Foundation Apache Directory LDAP API
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.
Affected software
Apache Software Foundation
Apache Directory LDAP API
pkg:maven/Apache Software Foundation/org.apache.directory.api:api-asn1-berRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves improper handling of BER-encoded LDAP responses in Apache Directory LDAP API. An attacker can send a small but maliciously crafted response that causes the client to allocate an excessively large amount of memory prematurely. This can result in an OutOfMemoryError that bypasses normal exception handling or cause the client to pin large memory allocations per connection, effectively exhausting the JVM heap and causing denial of service. The flaw affects versions from 1.2.0 up to but excluding 1.2.9. The vulnerability is addressed by upgrading to version 1.2.9.
Potential Impact
Exploitation of this vulnerability can lead to denial of service on the client side by exhausting JVM heap memory. This can disrupt normal operation of applications using the affected LDAP API. There is no indication of remote code execution or data compromise. The denial of service can be triggered by unauthenticated attackers sending crafted LDAP responses, including man-in-the-middle scenarios.
Mitigation Recommendations
Users should upgrade Apache Directory LDAP API to version 1.2.9 or later, which contains the fix for this vulnerability. No other mitigations or workarounds are specified. Applying the official fix fully addresses the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-09-29T16:17:56.332Z
- State
- PUBLISHED
Threat ID: 6abf7d8da43b0b3b899e5d48
Added to database: 10/02/2026, 09:46:53 UTC
Last enriched: 10/02/2026, 10:01:46 UTC
Last updated: 10/03/2026, 03:45:56 UTC
Views: 17
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