Medium severity · published Aug 12, 2026
CVE-2026-18663
389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical session tracking control
5.9
CVSS
0.5%
EPSS
No
On KEV
Description
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 then frees the same pointer again, causing a double-free. An unauthenticated remote attacker can trigger this with a single BIND request carrying a critical Session Tracking control, resulting in heap corruption and potential denial of service.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Directory Server 13 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18663
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-18663
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-18663
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2510631
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