Quick answers
- Is CVE-2026-102731 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-102731 being exploited in the wild.
- How severe is CVE-2026-102731?
- Informational severity, published 2 October 2026.
- Which products and versions are affected?
- Apache Directory Ldap Api 1.2.0 to 1.2.8.
- Is there a fix for CVE-2026-102731?
- Yes: fixed in 1.2.9. Until then: Set the MAX_PDU_SIZE_ATTR configuration attribute on embedding LDAP servers to limit the maximum size of protocol data units and prevent excessive memory allocation. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-102731 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-102731?
- Check whether you run Apache Directory Ldap Api at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 1.2.9
Set the MAX_PDU_SIZE_ATTR configuration attribute on embedding LDAP servers to limit the maximum size of protocol data units and prevent excessive memory allocation.
Technical details
The vulnerability exists in BER (Basic Encoding Rules) decoding where a size value in the message can be parsed before the actual data is received, causing the JVM to pre-allocate a large buffer. An unauthenticated attacker can exploit this by sending malformed LDAP responses, bypassing normal exception handlers and exhausting heap memory per connection. The issue affects Apache Directory LDAP API versions 1.2.0 through 1.2.8; version 1.2.9 contains the fix.
Affected products
- Apache Directory LDAP API 1.2.0 to 1.2.8
Timeline
- 2026-10-02: disclosed