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Review reviewHigh

CVE-2026-9064

Red Hat 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

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.

CVSS
7.5
EPSS
0.81%
52.9% percentile
CISA KEV
Not listed
Published
2026.05.20
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.81%
Technical severityCVSS 7.5

Vulnerability overview

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 product and versions

Product
Red Hat 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
Affected versions
11.0, 12.0, 13.0, 6.0, 7.0, 8.0, 9.0, 10.0
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Red Hat 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 and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
CWE-770
CVE-2026-9064 — Red Hat 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 | SECUFOCUS NOW