Fedora 43 : nsd (2026-3ff003d397)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##
# The descriptive text and package checks in this plugin were
# extracted from Fedora Security Advisory FEDORA-2026-3ff003d397
#

include('compat.inc');

if (description)
{
  script_id(343792);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/08");

  script_cve_id(
    "CVE-2026-18664",
    "CVE-2026-18916",
    "CVE-2026-19401",
    "CVE-2026-19538"
  );
  script_xref(name:"FEDORA", value:"2026-3ff003d397");

  script_name(english:"Fedora 43 : nsd (2026-3ff003d397)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Fedora host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the
FEDORA-2026-3ff003d397 advisory.

    BUG FIXES:

        Fix for CVE-2026-18664: IP range access control restrictions are bypassed for some unintended IP.
        Thanks to Qifan Zhang, Palo Alto Networks for the report
        Thanks to Claude and Ada Logics for the report
        https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-18664.txt
        Fix for CVE-2026-18916: Any remote client can denial TCP service by throttling the TCP receive window
    (down to 1).
        Thanks to Akhil Koul (https://github.com/akoul) for the report
        https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-18916.txt
        Fix for CVE-2026-19401: Any remote client can denial UDP service by sending a specifically crafted
    query with multiple DNS Cookie options.
        Thanks to Qifan Zhang, Palo Alto Networks for the report
        Thanks to afldl [email protected] for the report
        https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19401.txt
        Fix for CVE-2026-19538: Anyone with access to the proxy protocol port over TCP or TLS can bypass
    BLOCKED access control items.
        Thanks to Qifan Zhang, Palo Alto Networks for the report
        https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19538.txt


Tenable has extracted the preceding description block directly from the Fedora 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://bodhi.fedoraproject.org/updates/FEDORA-2026-3ff003d397");
  script_set_attribute(attribute:"solution", value:
"Update the affected nsd package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  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:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-18916");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-19538");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/08/26");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/28");
  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:fedoraproject:fedora:43");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:nsd");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Fedora 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");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include('rpm2.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) || 'Fedora' >!< os_product) audit(AUDIT_OS_NOT, 'Fedora');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
if (! preg(pattern:"^43([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Fedora 43', 'Fedora ' + 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) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Fedora', cpu);

var constraints = [
  {
    'release': '43',
    'pkgs': [
      {'reference':'nsd-4.15.1-1.fc43', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

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 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;
  }
  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 &&
        ## (no known rpm to check OR known rpm_exists)
        (!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)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'nsd');
}