CVE-2026-102731 PUBLISHED

Apache Directory LDAP API: Denial of service via excessive memory allocation in BER decode

Assigner: apache
Reserved: 29.09.2026 Published: 02.10.2026 Updated: 02.10.2026

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.

Product Status

Vendor Apache Software Foundation
Product Apache Directory LDAP API
Versions Default: unaffected
  • affected from 1.2.0 to 1.2.9 (excl.)

Credits

  • Claude Security tool
  • The Apache Software Foundation finder

References

Problem Types

  • CWE-789 Memory allocation with excessive size value CWE