CVE-2026-9064: 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 contr...

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.81%

52.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-770

Affected Software

Vendor	Product	Versions
Redhat	Directory Server	11.0
Redhat	Directory Server	12.0
Redhat	Directory Server	13.0
Redhat	389 Directory Server	All versions
Redhat	Enterprise Linux	6.0
Redhat	Enterprise Linux	7.0
Redhat	Enterprise Linux	8.0
Redhat	Enterprise Linux	9.0
Redhat	Enterprise Linux	10.0

References

Timeline

Published: May 20, 2026
Last Modified: Jun 18, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2026-9064?

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.

How severe is CVE-2026-9064?

CVE-2026-9064 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.81% probability of exploitation in the next 30 days.

How do I fix CVE-2026-9064?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.