Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : lwIP vulnerabilities (USN-8423-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8423-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(320846);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/13");

  script_cve_id(
    "CVE-2020-8597",
    "CVE-2020-22283",
    "CVE-2020-22284",
    "CVE-2026-8836"
  );
  script_xref(name:"USN", value:"8423-1");
  script_xref(name:"CEA-ID", value:"CEA-2020-0025");

  script_name(english:"Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : lwIP vulnerabilities (USN-8423-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by
multiple vulnerabilities as referenced in the USN-8423-1 advisory.

    It was discovered that lwIP contained a buffer overflow in the EAP authentication handling code. An
    attacker could possibly use this issue to trigger a buffer overflow, resulting in arbitrary code execution
    or a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2020-8597)

    It was discovered that lwIP incorrectly handled certain ICMPv6 or 6LoWPAN packets. An attacker could
    possibly use this issue to trigger a buffer overflow, resulting in information disclosure. This issue only
    affected Ubuntu 20.04 LTS. (CVE-2020-22283, CVE-2020-22284)

    It was discovered that lwIP did not properly validate certain SNMPv3 authentication parameters. An
    attacker could possibly use this issue to trigger a stack-based buffer overflow, resulting in arbitrary
    code execution or a denial of service. (CVE-2026-8836)

Tenable has extracted the preceding description block directly from the Ubuntu 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://ubuntu.com/security/notices/USN-8423-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected liblwip-dev, liblwip0 and / or liblwip0t64 packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-8597");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-8836");

  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:"2020/02/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:liblwip-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:liblwip0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:liblwip0t64");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2026 Canonical, Inc. / NASL script (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "ubuntu_pro_sub_detect.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('20.04' >< os_release || '22.04' >< os_release || '24.04' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04 / 22.04 / 24.04 / 26.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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, 'Ubuntu', cpu);
var ubuntu_pro_detected = get_kb_item('Host/Ubuntu/Pro/Services/esm-apps');
ubuntu_pro_detected = !empty_or_null(ubuntu_pro_detected);

var pro_caveat_needed = FALSE;

var pkgs = [
    {'osver': '20.04', 'pkgname': 'liblwip-dev', 'pkgver': '2.1.2+dfsg1-4ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2020-8597', 'CVE-2020-22283', 'CVE-2020-22284', 'CVE-2026-8836']},
    {'osver': '20.04', 'pkgname': 'liblwip0', 'pkgver': '2.1.2+dfsg1-4ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2020-8597', 'CVE-2020-22283', 'CVE-2020-22284', 'CVE-2026-8836']},
    {'osver': '22.04', 'pkgname': 'liblwip-dev', 'pkgver': '2.1.3+dfsg1-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-8836']},
    {'osver': '22.04', 'pkgname': 'liblwip0', 'pkgver': '2.1.3+dfsg1-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-8836']},
    {'osver': '24.04', 'pkgname': 'liblwip-dev', 'pkgver': '2.2.0+dfsg1-6.1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-8836']},
    {'osver': '24.04', 'pkgname': 'liblwip0t64', 'pkgver': '2.2.0+dfsg1-6.1ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-8836']},
    {'osver': '26.04', 'pkgname': 'liblwip-dev', 'pkgver': '2.2.1+dfsg1-4ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-8836']},
    {'osver': '26.04', 'pkgname': 'liblwip0t64', 'pkgver': '2.2.1+dfsg1-4ubuntu0.1~esm1', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-8836']}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  var pro_required = NULL;
  if (!empty_or_null(package_array['ubuntu_pro'])) pro_required = package_array['ubuntu_pro'];
  if (osver && pkgname && pkgver) {
    if (deb_check(release:osver, prefix:pkgname, reference:pkgver, cves:cves)) {
        flag++;
        if (!ubuntu_pro_detected && !pro_caveat_needed) pro_caveat_needed = pro_required;
    }
  }
}

if (flag)
{
  var extra = '';
  if (pro_caveat_needed) {
    extra += 'NOTE: This vulnerability check contains fixes that apply to packages only \n';
    extra += 'available in Ubuntu ESM repositories. Access to these package security updates \n';
    extra += 'require an Ubuntu Pro subscription.\n\n';
  }
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'liblwip-dev / liblwip0 / liblwip0t64');
}