CVE-2026-11791 389-ds-base: 389-ds-base: use-after-free in schema reload via attr_syntax_swap_ht()

Description

A flaw was found in 389 Directory Server. During schema reload, the attr_syntax_swap_ht() function unconditionally frees attribute syntax information nodes, bypassing the refcount-based deferred deletion used elsewhere in the attribute syntax subsystem. If an administrator triggers schema reload while concurrent LDAP query traffic is active, worker threads may access freed memory, resulting in use-after-free or double-free and a denial of service (server crash).

Exploitable remotely over the network, with an administrator account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Network

Attack complexity

High

Privileges required

High

Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

High

Affected products and versions