Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API.
A LDAP server using the LDAP API (like Apache DS) may consume 100% of a CPU core indefinitely when processing some badly crafted Telephone Numbers.
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.
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.
Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API.
Storing a password using the bcrypt algorithm with a high force like 30 in a LDAP server that supports this algorithm will cause the server CPU to run for hours checking the credentials. A bounded cost should be enforced to avoid a server DOS.
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.
Cleartext transmission of sensitive information vulnerability in Apache Directory LDAP API.
A StartTLS extended operation started after a Search request has been sent can lead to receive data in plain text before the TLS Handshake has been completed.
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.
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 MAXPDUSIZEATTR.
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.
Stack Overflow vulnerability in Apache Directory LDAP API.
Before binding, a client can send a deeply nested search filter that overflows the stack in the server's decoder.
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.
Severity: important
Affected versions:
- Apache Directory LDAP API 2.1.0 before 2.1.9
Description:
Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API.
A LDAP server using the LDAP API (like Apache DS) may consume 100% of a CPU core indefinitely when processing some badly crafted Telephone Numbers.
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.
This issue is being tracked as CWE-405 Asymmetric Resource Consumption (Amplification)
Credit:
Claude Security (tool) The Apache Software Foundation (finder)
References:
https://directory.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-103885 https://issues.apache.org/jira/browse/CWE-405 Asymmetric Resource Consumption (Amplification)
Severity: important
Affected versions:
- Apache Directory LDAP API 2.1.0 before 2.1.9
Description:
Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API.
Storing a password using the bcrypt algorithm with a high force like 30 in a LDAP server that supports this algorithm will cause the server CPU to run for hours checking the credentials. A bounded cost should be enforced to avoid a server DOS.
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.
Credit:
Claude Security (tool) The Apache Software Foundation (finder)
References:
https://directory.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-103880
Severity: important
Affected versions:
- Apache Directory LDAP API 2.1.0 before 2.1.9
Description:
Cleartext transmission of sensitive information vulnerability in Apache Directory LDAP API.
A StartTLS extended operation started after a Search request has been sent can lead to receive data in plain text before the TLS Handshake has been completed.
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.
Credit:
Claude Security (tool) The Apache Software Foundation (finder)
References:
https://directory.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-103878
Severity: critical
Affected versions:
- Apache Directory LDAP API 2.1.0 before 2.1.9
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.
Credit:
Claude Security (tool) The Apache Software Foundation (finder)
References:
https://directory.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-103877
Severity: critical
Affected versions:
- Apache Directory LDAP API 1.2.0 before 1.2.9
Description:
Stack Overflow vulnerability in Apache Directory LDAP API.
Before binding, a client can send a deeply nested search filter that overflows the stack in the server's decoder.
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.
Credit:
Claude Security (tool) The Apache Software Foundation (finder)
References:
https://directory.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-103552
Severity: critical
Affected versions:
- Apache Directory LDAP API 1.2.0 before 1.2.9
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 MAXPDUSIZEATTR.
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.
Credit:
Claude Security (tool) The Apache Software Foundation (finder)
References:
https://directory.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-102731
It was identified that the LDAP client implementation in version 2.1.7 does not verify if the server certificate matches the intended LDAP hostname. While the underlying code validates the certificate chain against a trusted authority, the absence of endpoint identification allows a valid certificate issued for an entirely unrelated host to be improperly accepted. This oversight leaves the connection highly vulnerable to server impersonation and complete connection compromise.
The root cause of this vulnerability lies in the incomplete TLS server identity verification within the LDAP client implementation.
The attacker requires MITM capability on the network to exploit this vulnerability. This attacker must be able to present a certificate trusted by the client's configured trust store.
The hostname verification has been enforced in the new version of the LDAP API
In Apache Directory LDAP API before 1.0.2, a bug in the way the SSL Filter was setup made it possible for another thread to use the connection before the TLS layer has been established, if the connection has already been used and put back in a pool of connections, leading to leaking any information contained in this request (including the credentials when sending a BIND request).
Apache Directory LDAP API before 1.0.0-M31 allows attackers to conduct timing attacks via unspecified vectors.