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RHEL 9 : 389-ds-base (RHSA-2026:64781)

🗓️ 08 Sep 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com

389-ds-base on RHEL 9: heap overflow, pre-auth NULL deref, privilege escalation, and ACI bypass.

Related
Refs
Code
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2026:64781. The text
# itself is copyright (C) Red Hat, Inc.
##

include('compat.inc');

if (description)
{
  script_id(343774);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/08");

  script_cve_id(
    "CVE-2026-18355",
    "CVE-2026-18453",
    "CVE-2026-18922",
    "CVE-2026-76560"
  );
  script_xref(name:"RHSA", value:"2026:64781");

  script_name(english:"RHEL 9 : 389-ds-base (RHSA-2026:64781)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as
referenced in the RHSA-2026:64781 advisory.

    389 Directory Server is an LDAP version 3 (LDAPv3) compliant server. The base packages include the
    Lightweight Directory Access Protocol (LDAP) server and command-line utilities for server administration.

    Security Fix(es):

    * 389-ds-base: 389-ds-base: heap buffer overflow via SASL wrapped-record length lower-bound underflow in
    sasl_io_start_packet() (CVE-2026-18355)

    * 389-ds-base: 389-ds-base: pre-authentication NULL pointer dereference via paged results and
    USE_ONE_BACKEND control in op_shared_search (CVE-2026-18453)

    * 389-ds-base: 389-ds-base: SASL PLAIN authentication allows privilege escalation to Directory Manager via
    stale identity in Cyrus SASL auxiliary property (CVE-2026-18922)

    * 389-ds-base: 389-ds: anonymous LDAP client can defeat SELFDN ACI bind-rule checks via empty bind DN
    (CVE-2026-76560)

    Bug Fix(es) and Enhancement(s):

    * lib389: set nsDS5ReplicaBindDNGroup before ensure_agreement() [rhel-9.4.z] (JIRA:RHEL-244465)

    * fix breaks replication total init when nsDS5ReplicaBindDNGroup is set after agreement creation
    [rhel-9.4.z] (JIRA:RHEL-248764)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and
    other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/updates/classification/#critical");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2509186");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2509696");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2511388");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2519521");
  # https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_64781.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?413395f6");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:64781");
  script_set_attribute(attribute:"solution", value:
"Update the affected 389-ds-base, 389-ds-base-libs and / or python3-lib389 packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-18922");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(191, 287, 476, 863);
  script_set_attribute(attribute:"vendor_severity", value:"Critical");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/07");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/08");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:rhel_e4s:9.4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:389-ds-base");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:389-ds-base-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python3-lib389");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Red Hat Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "redhat_repos.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');
include('rhel.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'Red Hat' >!< os_product) audit(AUDIT_OS_NOT, 'Red Hat');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat');
if (!rhel_check_release(operator: 'eq', os_version: os_version, rhel_version: '9.4')) audit(AUDIT_OS_NOT, 'Red Hat 9.4', 'Red Hat ' + os_version);

if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu);

var constraints = [
  {
    'release': '9',
    'sp': '4',
    'repo_relative_urls': [
      'content/aus/rhel9/9.4/x86_64/appstream/debug',
      'content/aus/rhel9/9.4/x86_64/appstream/os',
      'content/aus/rhel9/9.4/x86_64/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/aarch64/appstream/debug',
      'content/e4s/rhel9/9.4/aarch64/appstream/os',
      'content/e4s/rhel9/9.4/aarch64/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/ppc64le/appstream/debug',
      'content/e4s/rhel9/9.4/ppc64le/appstream/os',
      'content/e4s/rhel9/9.4/ppc64le/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/s390x/appstream/debug',
      'content/e4s/rhel9/9.4/s390x/appstream/os',
      'content/e4s/rhel9/9.4/s390x/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/x86_64/appstream/debug',
      'content/e4s/rhel9/9.4/x86_64/appstream/os',
      'content/e4s/rhel9/9.4/x86_64/appstream/source/SRPMS',
      'content/e6s/rhel9/9.4/aarch64/appstream/debug',
      'content/e6s/rhel9/9.4/aarch64/appstream/os',
      'content/e6s/rhel9/9.4/aarch64/appstream/source/SRPMS',
      'content/e6s/rhel9/9.4/ppc64le/appstream/debug',
      'content/e6s/rhel9/9.4/ppc64le/appstream/os',
      'content/e6s/rhel9/9.4/ppc64le/appstream/source/SRPMS',
      'content/e6s/rhel9/9.4/s390x/appstream/debug',
      'content/e6s/rhel9/9.4/s390x/appstream/os',
      'content/e6s/rhel9/9.4/s390x/appstream/source/SRPMS',
      'content/e6s/rhel9/9.4/x86_64/appstream/debug',
      'content/e6s/rhel9/9.4/x86_64/appstream/os',
      'content/e6s/rhel9/9.4/x86_64/appstream/source/SRPMS'
    ],
    'pkgs': [
      {'reference':'389-ds-base-2.4.5-29.el9_4', 'sp':'4', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'389-ds-base-libs-2.4.5-29.el9_4', 'sp':'4', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-lib389-2.4.5-29.el9_4', 'sp':'4', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var applicable_repo_urls = rhel_determine_applicable_repository_urls(constraints:constraints);
if(applicable_repo_urls == RHEL_REPOS_NO_OVERLAP_MESSAGE) exit(0, RHEL_REPO_NOT_ENABLED);

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var repo_relative_urls;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }

  if (!empty_or_null(constraint['repo_relative_urls'])) repo_relative_urls = constraint['repo_relative_urls'];

  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        rhel_decide_repo_relative_url_check(required_repo_url_list:repo_relative_urls) &&
        (applicable_repo_urls || (!exists_check || rpm_exists(rpm:exists_check))) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  var subscription_caveat = '\n' +
    'NOTE: This vulnerability check contains fixes that apply to\n' +
    'packages only available in the Red Hat Enterprise Linux\n' +
    'Update Services for SAP Solutions repository.\n' +
    'Access to this repository requires a paid RHEL subscription.\n';
  var extra = NULL;
  if (isnull(applicable_repo_urls) || !applicable_repo_urls) extra = subscription_caveat + rpm_report_get() + redhat_report_repo_caveat();
  else extra = subscription_caveat + rpm_report_get();
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : extra
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, '389-ds-base / 389-ds-base-libs / python3-lib389');
}

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