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Fencer Vulns
medium 5.9

CVE-2026-18663 json

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

published 2026-08-12 2 mo ago modified 2026-11-05 3 d ago also EUVD-2026-57153

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

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.

Patch / fix

  • 389-ds openSUSE Tumbleweed 3.3.1+8c2711bd6-1.1

opensuse advisories openSUSE-SU-2026:11739-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-18663 updated cvss 5.9

389-ds-base: 389-ds-base: pre-authentication double-free in get_ldapmessage_controls_ext() via critical Session Tracking control

  • Red Hat Directory Server 13 389-ds-base Red Hat Enterprise Linux 10 389-ds-base
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Directory Server 11 389-ds-base Red Hat Directory Server 12 389-ds-base Red Hat Enterprise Linux 6 389-ds-base, 389-ds-base-libs Red Hat Enterprise Linux 7 389-ds-base, 389-ds-base-libs, 389-ds-base-snmp Red Hat Enterprise Linux 8 389-ds-base, cockpit-389-ds, python3-lib389, 389-ds-base-libs, 389-ds-base-snmp, 389-ds-base-legacy-tools Red Hat Enterprise Linux 9 389-ds-base, python3-lib389, 389-ds-base-libs, 389-ds-base-snmp
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

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

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.