Medium [CVE-2026-11788] 389-ds-base: 389-ds-base: null pointer dereference in deref control plugin ber parser
This medium-severity Red Hat Linux advisory covers CVE-2026-11788 affecting Red Hat Directory Server 11.7 E4S for RHEL 8, Red Hat Directory Server 11.9 for RHEL 8, Red Hat Directory Server 12.2 E4S for RHEL 9.
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Summary
A flaw was found in 389 Directory Server. The dereference control plugin does not check for allocation failure before using a BER structure, allowing an unauthenticated remote attacker to crash the LDAP server when the system is under memory pressure.
Red Hat rates this issue as Moderate impact. If allocation fails, an LDAP search carrying the deref control can crash ns-slapd.
The deref plugin is enabled by default, and anonymous clients can send the control when anonymous access is allowed. Natural OOM was not demonstrated end-to-end without fault injection.
Disabling the deref plugin removes the vulnerable code path entirely. Red Hat severity: Moderate — CVSS 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-476.
Affected products named by the advisory: Red Hat Directory Server 11.7 E4S for RHEL 8; Red Hat Directory Server 11.9 for RHEL 8; Red Hat Directory Server 12.2 E4S for RHEL 9; Red Hat Directory Server 12.4 E4S for RHEL 9; and 14 more.
Affected products named by the advisory: Red Hat Enterprise Linux 10.0 Extended Update Support; Red Hat Enterprise Linux 7 Extended Lifecycle Support; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support; Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On; and 10 more.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
- redhat-ds:11-8080020260806114250.f969626e
- redhat-ds:11-8100020260803140625.37ed7c03
- redhat-ds:12-9020020260730155601.1674d574
- redhat-ds:12-9040020260810131422.1674d574
- 389-ds-base-0:3.2.0-9.el10_2
- 389-ds-base-0:3.0.6-20.el10_0
- 389-ds-base-0:1.3.11.1-14.el7_9
- 389-ds:1.4-8100020260806150504.25e700aa
- 389-ds:1.4-8040020260803141511.96015a92
- 389-ds:1.4-8060020260806120442.824efc52
- 389-ds:1.4-8080020260806114228.6dbb3803
- 389-ds-base-0:2.8.0-9.el9_8
- 389-ds-base-0:2.2.4-20.el9_2
- 389-ds-base-0:2.4.5-27.el9_4
- 389-ds-base-0:2.6.1-23.el9_6
- RHSA-2026:56047
- RHSA-2026:55532
- RHSA-2026:56048
- RHSA-2026:56050
- RHSA-2026:55424
- RHSA-2026:55425
- RHSA-2026:55758
- RHSA-2026:55530
- RHSA-2026:55757
- RHSA-2026:55756
- RHSA-2026:55794
- RHSA-2026:55423
- RHSA-2026:55421
- RHSA-2026:55422
- RHSA-2026:55426
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- Disable the deref plugin (most effective): dsconf <instance> plugin deref disable; systemctl restart dirsrv@<instance>. Disable anonymous access (nsslapd-allow-anonymous-access=off) to raise the bar from pre-auth to authenticated exploitation. Configure memory limits as defense-in-depth: set nsslapd-maxbersize and nsslapd-conntablesize, and deploy in a cgroup with memory limits.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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