Ubuntu 26.04 LTS : Tomcat vulnerabilities (USN-8450-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8450-1. 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(321761);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/20");

  script_cve_id(
    "CVE-2026-41284",
    "CVE-2026-41293",
    "CVE-2026-42498",
    "CVE-2026-43515"
  );
  script_xref(name:"IAVA", value:"2026-A-0475");
  script_xref(name:"USN", value:"8450-1");

  script_name(english:"Ubuntu 26.04 LTS : Tomcat vulnerabilities (USN-8450-1)");

  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 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in
the USN-8450-1 advisory.

    It was discovered that Tomcat did not properly limit the size of WebDAV LOCK and PROPFIND request bodies.
    A remote attacker could possibly use this issue to cause Tomcat to consume excessive memory, resulting in
    a denial of service. (CVE-2026-41284)

    It was discovered that Tomcat incorrectly validated HTTP/2 header fields. A remote attacker could use this
    issue to cause Tomcat to crash or possibly execute arbitrary code. (CVE-2026-41293)

    It was discovered that Tomcat did not properly clear HTTP authentication headers during WebSocket
    connection upgrades and redirects. A remote attacker could possibly use this issue to obtain sensitive
    credentials. (CVE-2026-42498)

    It was discovered that Tomcat incorrectly handled authorization when multiple method constraints defined
    the same HTTP method. A remote attacker could possibly use this issue to bypass authorization
    restrictions. (CVE-2026-43515)

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-8450-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected 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: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:"cvss_score_source", value:"CVE-2026-41293");

  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:"2026/05/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:libtomcat11-embed-java");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libtomcat11-java");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat11");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat11-admin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat11-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat11-examples");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:tomcat11-user");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  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 (! ('26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 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': '26.04', 'pkgname': 'libtomcat11-embed-java', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
    {'osver': '26.04', 'pkgname': 'libtomcat11-java', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
    {'osver': '26.04', 'pkgname': 'tomcat11', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
    {'osver': '26.04', 'pkgname': 'tomcat11-admin', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
    {'osver': '26.04', 'pkgname': 'tomcat11-common', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
    {'osver': '26.04', 'pkgname': 'tomcat11-examples', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE},
    {'osver': '26.04', 'pkgname': 'tomcat11-user', 'pkgver': '11.0.18-1ubuntu0.1~esm1', 'ubuntu_pro': TRUE}
];

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, 'libtomcat11-embed-java / libtomcat11-java / tomcat11 / etc');
}