CVE-2026-102731
UnknownSummary
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, leading to OutOfMemoryError and denial of service. This issue affects versions from 1.2.0 before 1.2.9.
Risk Assessment
An attacker can exhaust the heap memory of the client JVM or embedding server, causing denial of service (DoS). A handful of connections can exhaust any heap, and the attack does not require authentication.
Recommendation
Upgrade Apache Directory LDAP API to version 1.2.9, which fixes the issue. Set the MAX_PDU_SIZE_ATTR attribute in embedding servers to limit the size of processed data.
Other vulnerabilities in Apache Directory LDAP API
See all- CVE-2026-103885Unknown
Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API. An 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 versions from 2.1.0 before 2.1.9. Users are recommended to upgrade to version 2.1.9.
- CVE-2026-103880Unknown
Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API. Storing a password using the bcrypt algorithm with a high force like 30 in an 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 versions from 2.1.0 before 2.1.9. Users are recommended to upgrade to version 2.1.9.
- CVE-2026-103878Unknown
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 versions from 2.1.0 before 2.1.9. Users are recommended to upgrade to version 2.1.9.
- CVE-2026-103877Unknown
Deserialization of Untrusted Data vulnerability in Apache Directory LDAP API. A rogue or compromised LDAP server (or a pre-TLS MITM) can answer a client's loadSchema() subschema search with a schema object containing a serialized Java class, potentially allowing RCE. This issue affects versions from 2.1.0 before 2.1.9.
- CVE-2026-103552Unknown
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 versions from 1.2.0 before 1.2.9.
- CVE-2015-3250High
Apache Directory LDAP API before version 1.0.0-M31 allows attackers to conduct timing attacks via unspecified vectors.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS