The Content Synchronization (syncrepl) persistent search plugin in 389 Directory Server contains three availability bugs in sync_persist.c:

Bug 1 (primary): Unbounded queue growth — an authenticated user opens a persistent sync search then stops reading responses; modification events queue without limit until memory exhaustion and server crash. Confirmed on UBI 8 and CentOS Stream 8 production binaries (+17MB measured from 500 mods).

Bug 2: sync_persist_terminate() dangling pointer race during connection teardown.

Bug 3: thread_count non-atomic increment/decrement during shutdown (weak memory model architectures).

Vulnerable code present since plugin introduction; no upstream fix as of 2026-04-22.