CVE-2026-11611: 389-ds-base: 389-ds-base: content sync plugin unbounded queue growth and race conditions
A flaw was found in 389 Directory Server. The Content Synchronization persistent search plugin allows unbounded memory growth when an authenticated client stops reading sync responses, enabling denial of service. Additional race conditions in plugin thread lifecycle can cause crashes during connection teardown or shutdown.
Other sources
The Content Synchronization (syncrepl) persistent search plugin in 389 Directory Server contains three availability bugs in syncpersist.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: syncpersistterminate() dangling pointer race during connection teardown.
Bug 3: threadcount non-atomic increment/decrement during shutdown (weak memory model architectures).
Vulnerable code present since plugin introduction; no upstream fix as of 2026-04-22.
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-11611?
The severity of CVE-2026-11611 is classified as medium, with a score of 6.5.
What type of issue is identified in CVE-2026-11611?
CVE-2026-11611 identifies a race condition and unbounded queue growth vulnerability in the 389 Directory Server.
How do I fix CVE-2026-11611?
To fix CVE-2026-11611, upgrade to the latest version of Red Hat 389-ds-base that addresses this vulnerability.
What impact does CVE-2026-11611 have on the system?
CVE-2026-11611 can lead to denial of service due to unbounded memory growth and potential crashes in the plugin thread.
Which software is affected by CVE-2026-11611?
CVE-2026-11611 affects Red Hat 389-ds-base.