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Vulnerability · Published May 20, 2026 · Assigned by redhat

CVE-2026-9064389-ds-base: 389-ds-base: unbounded ldap controls count in get_ldapmessage_controls_ext() causes cpu and heap amplification (remote dos)

High 7.5

In plain English

A high-severity resource allocation without limits in 389-ds-base. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 57% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.8%top 42.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function in the LDAP server does not enforce an upper bound on the number of controls per LDAP message. A remote, unauthenticated attacker can send a specially crafted LDAP request containing hundreds of thousands of minimal controls within the default maximum BER message size (2 MB), causing excessive CPU consumption and heap allocation on the server. Under concurrent exploitation, this leads to significant latency degradation, worker thread starvation, or out-of-memory termination, resulting in a denial of service.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:8389-ds-base1.4.3.39-24.module_el8.10.0+4196+be88fbc7ALSA-2026:26459
AlmaLinux:9389-ds-base2.8.0-7.el9_8ALSA-2026:26455
AlmaLinux:8389-ds-base-devel1.4.3.39-24.module_el8.10.0+4196+be88fbc7ALSA-2026:26459
AlmaLinux:9389-ds-base-devel2.8.0-7.el9_8ALSA-2026:26455
AlmaLinux:8389-ds-base-legacy-tools1.4.3.39-24.module_el8.10.0+4196+be88fbc7ALSA-2026:26459
AlmaLinux:8389-ds-base-libs1.4.3.39-24.module_el8.10.0+4196+be88fbc7ALSA-2026:26459
AlmaLinux:9389-ds-base-libs2.8.0-7.el9_8ALSA-2026:26455
AlmaLinux:8389-ds-base-snmp1.4.3.39-24.module_el8.10.0+4196+be88fbc7ALSA-2026:26459
AlmaLinux:9389-ds-base-snmp2.8.0-7.el9_8ALSA-2026:26455
AlmaLinux:8python3-lib3891.4.3.39-24.module_el8.10.0+4196+be88fbc7ALSA-2026:26459
AlmaLinux:9python3-lib3892.8.0-7.el9_8ALSA-2026:26455
Debian:12389-ds-baseno fix listedDEBIAN-CVE-2026-9064
Debian:13389-ds-baseno fix listedDEBIAN-CVE-2026-9064
Rocky Linux:10389-ds-base0:3.2.0-7.el10_2RLSA-2026:26456
Rocky Linux:8389-ds-base0:1.4.3.39-24.module+el8.10.0+40214+a8ec6bf9RLSA-2026:26459
Rocky Linux:9389-ds-base0:2.8.0-7.el9_8RLSA-2026:26455
Ubuntu:22.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-9064
Ubuntu:24.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-9064
Ubuntu:25.10389-ds-baseno fix listedUBUNTU-CVE-2026-9064
Ubuntu:26.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-9064
Ubuntu:26.10389-ds-baseno fix listedUBUNTU-CVE-2026-9064

Affected products (as reported)

VendorProductVersions
389-ds-base 0
Red Hat Red Hat Directory Server 11.5 E4S for RHEL 8 see references
Red Hat Red Hat Directory Server 11.7 E4S for RHEL 8 see references
Red Hat Red Hat Directory Server 11.9 for RHEL 8 see references
Red Hat Red Hat Directory Server 12.2 E4S for RHEL 9 see references
Red Hat Red Hat Directory Server 12.4 E4S for RHEL 9 see references
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support see references
Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support see references
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On see references
Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support see references
Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On see references
Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service see references
Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 9 see references
Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions see references
Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support see references
Red Hat Red Hat Directory Server 13.2 see references
Red Hat Red Hat Directory Server 12 see references
Red Hat Red Hat Directory Server 13 see references
Red Hat Red Hat Enterprise Linux 6 see references

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References