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Vulnerability · Published Aug 12, 2026 · Assigned by redhat

CVE-2026-18663389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical session tracking control

Medium 5.9

In plain English

A medium-severity double free in Red Hat Directory Server 11 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.5%top 56.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12389-ds-baseno fix listedDEBIAN-CVE-2026-18663
Debian:13389-ds-baseno fix listedDEBIAN-CVE-2026-18663
Ubuntu:22.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-18663
Ubuntu:24.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-18663
Ubuntu:26.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-18663
Ubuntu:26.10389-ds-baseno fix listedUBUNTU-CVE-2026-18663

Affected products (as reported)

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

Weakness: CWE-415 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References