Amazon Linux 2023 : perl-Net-CIDR-Lite (ALAS2023-2026-1624)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2026-1624.
##

include('compat.inc');

if (description)
{
  script_id(311311);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/30");

  script_cve_id("CVE-2026-40198", "CVE-2026-40199");

  script_name(english:"Amazon Linux 2023 : perl-Net-CIDR-Lite (ALAS2023-2026-1624)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2023 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1624 advisory.

    Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL
    bypass.

    _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups.
    Inputs like abcd, 1:2:3, or 1:2:3:4:5:6:7 are accepted and produce packed values of wrong length (3,
    7, or 15 bytes instead of 17).

    The packed values are used internally for mask and comparison operations. find() and bin_find() use Perl
    string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results.
    This can cause find() to incorrectly report an address as inside or outside a range.

    Example:

    my $cidr = Net::CIDR::Lite->new(::/8);$cidr->find(1:2:3);  # invalid input, incorrectly returns true

    This is the same class of input validation issue as CVE-2021-47154 (IPv4 leading zeros) previously fixed
    in this module.

    See also CVE-2026-40199, a related issue in the same function affecting IPv4 mapped IPv6 addresses.
    (CVE-2026-40198)

    Net::CIDR::Lite versions before 0.23 for Perl mishandles IPv4 mapped IPv6 addresses, which may allow IP
    ACL bypass.

    _pack_ipv6() includes the sentinel byte from _pack_ipv4() when building the packed representation of IPv4
    mapped addresses like ::ffff:192.168.1.1. This produces an 18 byte value instead of 17 bytes, misaligning
    the IPv4 part of the address.

    The wrong length causes incorrect results in mask operations (bitwise AND truncates to the shorter
    operand) and in find() / bin_find() which use Perl string comparison (lt/gt). This can cause find() to
    incorrectly match or miss addresses.

    Example:

    my $cidr = Net::CIDR::Lite->new(::ffff:192.168.1.0/120);$cidr->find(::ffff:192.168.2.0);  #
    incorrectly returns true

    This is triggered by valid RFC 4291 IPv4 mapped addresses (::ffff:x.x.x.x).

    See also CVE-2026-40198, a related issue in the same function affecting malformed IPv6 addresses.
    (CVE-2026-40199)

Tenable has extracted the preceding description block directly from the tested product 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://alas.aws.amazon.com//AL2023/ALAS2023-2026-1624.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-40198.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-40199.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update perl-Net-CIDR-Lite --releasever 2023.11.20260427' or
  or 'dnf update --advisory ALAS2023-2026-1624 --releasever 2023.11.20260427' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N");
  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:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-40198");

  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:"2026/04/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:perl-Net-CIDR-Lite");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Amazon 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/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "-2023")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2023", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'perl-Net-CIDR-Lite-0.22-8.amzn2023.0.1', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (reference && _release && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    if (rpm_check(release:_release, 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, "perl-Net-CIDR-Lite");
}