CVE-2026-102731
Apache Directory LDAP API: Denial of service via excessive memory allocation in BER decode
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
Apache Directory LDAP API: Denial of service via excessive memory allocation in BER decode
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.
- Record
CVE-2026-102731- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-789
- Updated
- 2026-11-02
EUVDEUVD-2026-91333
7.5
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.
- Record
EUVD-2026-91333- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-h24g-pjpf-8f2m
7.5
Memory allocation with excessive size value vulnerability in Apache Directory LDAP API. A...
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.
- Record
GHSA-h24g-pjpf-8f2m- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-789
- Updated
- 2026-11-02
NVD
7.5
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.
- Record
CVE-2026-102731- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-789
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-102731
7.5
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.
- Record
DEBIAN-CVE-2026-102731- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-102731
7.5
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.
- Record
UBUNTU-CVE-2026-102731- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
apache-directory-apiDebian:12 |
All versions, plus listed versions 2.1.2-12.1.2-2 |
None known |
apache-directory-apiDebian:13 |
All versions, plus listed versions 2.1.2-2 |
None known |
apache-directory-apiDebian:14 |
All versions, plus listed versions 2.1.2-2 |
None known |
apache-directory-apiUbuntu:16.04:LTS |
All versions, plus listed versions 1.0.0~M20-3 |
None known |
apache-directory-apiUbuntu:18.04:LTS |
All versions, plus listed versions 1.0.0~M20-51.0.0-1 |
None known |
apache-directory-apiUbuntu:20.04:LTS |
All versions, plus listed versions 1.0.0-1 |
None known |
apache-directory-apiUbuntu:22.04:LTS |
All versions, plus listed versions 1.0.0-2 |
None known |
apache-directory-apiUbuntu:24.04:LTS |
All versions, plus listed versions 2.1.2-1 |
None known |
apache-directory-apiUbuntu:26.10 |
All versions, plus listed versions 2.1.2-2build1 |
None known |
apache-directory-apiUbuntu:26.04:LTS |
All versions, plus listed versions 2.1.2-22.1.2-2build1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-102731 is a high vulnerability (CVSS 7.5) in Apache Software Foundation Directory Ldap Api, published October 2, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. No source names a fixed version.
References
lists.apache.org/thread.html/b8kg8881pc0v8lp59w0fcfrs69wjbqvd
openwall.com/lists/oss-security/2026/10/02/3
nvd.nist.gov/vuln/detail/CVE-2026-102731
github.com/advisories/GHSA-h24g-pjpf-8f2m
security-tracker.debian.org/tracker/CVE-2026-102731
ubuntu.com/security/CVE-2026-102731
cve.org/CVERecord?id=CVE-2026-102731