389-DS LDAP DoS: Unbounded Controls Enable Remote Overload
CVE-2026-9064 Published on May 20, 2026

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

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Vulnerability Analysis

CVE-2026-9064 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public. 76 days later.

Weakness Type

Allocation of Resources Without Limits or Throttling

The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.


Products Associated with CVE-2026-9064

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Red Hat Directory Server
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Directory Server E4s
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel Aus
 
Red Hat Rhel Eus Long Life
 
Red Hat Rhel E4s
 
Red Hat Rhel Els
 
Red Hat Rhel Tus
 
Red Hat Rhel Eus
 

Affected Versions

Red Hat Directory Server 11.5 E4S for RHEL 8: 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: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 7 Extended Lifecycle Support: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Directory Server 13.2: Red Hat Directory Server 12: Red Hat Directory Server 13: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux Server (v. 7 ELS): Red Hat Enterprise Linux Server Optional (v. 7 ELS): Red Hat Directory Server 11.9 for RHEL 8: Red Hat Enterprise Linux AppStream EUS (v. 10.0): Red Hat Enterprise Linux AppStream (v. 10): Red Hat Enterprise Linux AppStream (v. 8): Red Hat Enterprise Linux AppStream AUS (v.8.4): Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4): Red Hat Enterprise Linux AppStream AUS (v.8.6): Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6): Red Hat Enterprise Linux AppStream E4S (v.8.8): Red Hat Enterprise Linux AppStream TUS (v.8.8): Red Hat Enterprise Linux AppStream E4S (v.9.2): Red Hat Enterprise Linux AppStream E4S (v.9.4): Red Hat Enterprise Linux AppStream EUS (v.9.6): Red Hat Enterprise Linux AppStream (v. 9): Red Hat Directory Server 11.5 E4S for RHEL 8: Red Hat Directory Server 11.7 E4S for RHEL 8: Red Hat Directory Server 12.2 E4S for RHEL 9: Red Hat Directory Server 12.4 E4S for RHEL 9: Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0): Red Hat Enterprise Linux CodeReady Linux Builder (v. 10): Red Hat CodeReady Linux Builder EUS (v.9.6): Red Hat Enterprise Linux CodeReady Linux Builder (v. 9): Red Hat Directory Server 13.2: Red Hat Directory Server 12: Red Hat Directory Server 13: Red Hat Enterprise Linux 6:

Exploit Probability

EPSS
0.81%
Percentile
52.27%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.