RockyLinux 9 : dnsmasq (RLSA-2026:19373)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# Rocky Linux Security Advisory RLSA-2026:19373.
##

include('compat.inc');

if (description)
{
  script_id(317980);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/29");

  script_cve_id(
    "CVE-2026-2291",
    "CVE-2026-4890",
    "CVE-2026-4891",
    "CVE-2026-4892",
    "CVE-2026-4893"
  );
  script_xref(name:"RLSA", value:"2026:19373");

  script_name(english:"RockyLinux 9 : dnsmasq (RLSA-2026:19373)");

  script_set_attribute(attribute:"synopsis", value:
"The remote RockyLinux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the
RLSA-2026:19373 advisory.

    * dnsmasq: dnsmasq: heap buffer overflow in cache via NAME_ESCAPE expansion (CVE-2026-2291)

    * dnsmasq: NSEC bitmap parsing infinite loop (CVE-2026-4890)

    * dnsmasq: RRSIG rdlen underflow leading to heap OOB read (CVE-2026-4891)

    * dnsmasq: DHCPv6 CLID buffer overflow in helper process (CVE-2026-4892)

    * dnsmasq: Broken ECS source validation bypass (CVE-2026-4893)

Tenable has extracted the preceding description block directly from the RockyLinux 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://errata.rockylinux.org/RLSA-2026:19373");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2439088");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2458516");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2458517");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2458518");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2458519");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-4892");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/05/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/05/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:dnsmasq");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:dnsmasq-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:dnsmasq-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:dnsmasq-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:rocky:linux:dnsmasq-utils-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:rocky:linux:9");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Rocky Linux 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/RockyLinux/release", "Host/RockyLinux/rpm-list", "Host/cpu");

  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) || 'Rocky Linux' >!< os_product) audit(AUDIT_OS_NOT, 'Rocky Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Rocky Linux');
if (! preg(pattern:"^9([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'RockyLinux 9.x', 'Rocky Linux ' + os_version);

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

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

var constraints = [
  {
    'release': '9',
    'pkgs': [
      {'reference':'dnsmasq-2.85-18.el9_8.1', 'cpu':'aarch64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-2.85-18.el9_8.1', 'cpu':'ppc64le', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-2.85-18.el9_8.1', 'cpu':'s390x', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-2.85-18.el9_8.1', 'cpu':'x86_64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debuginfo-2.85-18.el9_8.1', 'cpu':'aarch64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debuginfo-2.85-18.el9_8.1', 'cpu':'ppc64le', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debuginfo-2.85-18.el9_8.1', 'cpu':'s390x', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debuginfo-2.85-18.el9_8.1', 'cpu':'x86_64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debugsource-2.85-18.el9_8.1', 'cpu':'aarch64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debugsource-2.85-18.el9_8.1', 'cpu':'ppc64le', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debugsource-2.85-18.el9_8.1', 'cpu':'s390x', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-debugsource-2.85-18.el9_8.1', 'cpu':'x86_64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-2.85-18.el9_8.1', 'cpu':'aarch64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-2.85-18.el9_8.1', 'cpu':'ppc64le', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-2.85-18.el9_8.1', 'cpu':'s390x', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-2.85-18.el9_8.1', 'cpu':'x86_64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-debuginfo-2.85-18.el9_8.1', 'cpu':'aarch64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-debuginfo-2.85-18.el9_8.1', 'cpu':'ppc64le', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-debuginfo-2.85-18.el9_8.1', 'cpu':'s390x', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'dnsmasq-utils-debuginfo-2.85-18.el9_8.1', 'cpu':'x86_64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
    ]
  }
];

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_HOLE,
      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, 'dnsmasq / dnsmasq-debuginfo / dnsmasq-debugsource / dnsmasq-utils / etc');
}