What is CVE-2026-18663?

CVE-2026-18663 is a medium-severity vulnerability in Red Hat Directory Server 11, classified under Double Free. CVSS score: 5.9/10. Published 2026-08-12.

How severe is CVE-2026-18663?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Double Free in Red Hat Directory Server 11

CVE-2026-18663

A flaw was found in 389-ds-base. The get_ldapmessage_controls_ext() function frees the parsed controls array on the Session Tracking critical-control rejection path without clearing the SLAPI_REQCONTROLS pblock slot. Operation teardown the…

Vulnerability class: Double Free

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Red Hat Directory Server 11
Red Hat Directory Server 12
Red Hat Directory Server 13
Red Hat Enterprise Linux 10
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8
Red Hat Enterprise Linux 9

Weakness classification (CWE)

CWE-415 — Double Free

References

secalert@redhat.com (x_refsource_REDHAT, vdb-entry)
secalert@redhat.com (x_refsource_REDHAT, issue-tracking)

Frequently asked questions

What is CVE-2026-18663?: CVE-2026-18663 is a medium-severity vulnerability in Red Hat Directory Server 11, classified under Double Free. CVSS score: 5.9/10. Published 2026-08-12.
How severe is CVE-2026-18663?: Medium severity. CVSS v3 base score is 5.9 out of 10.