Linux Distros Unpatched Vulnerability : CVE-2026-84642

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(342526);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/03");

  script_cve_id("CVE-2026-84642");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-84642");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular
    expression without escaping. For some possible valid hostnames, this could allow certain unintended
    hostnames to also match and serve remote attachments. This vulnerability was fixed in Thunderbird 155 and
    Thunderbird 153.2. (CVE-2026-84642)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-84642");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  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:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-84642");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/03");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:thunderbird");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04", "Host/OS/Ubuntu Linux-26.04");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-dbg"},
          {"reference": "thunderbird-dev"},
          {"reference": "thunderbird-gnome-support"},
          {"reference": "thunderbird-gnome-support-dbg"},
          {"reference": "thunderbird-locale-af"},
          {"reference": "thunderbird-locale-ar"},
          {"reference": "thunderbird-locale-ast"},
          {"reference": "thunderbird-locale-be"},
          {"reference": "thunderbird-locale-bg"},
          {"reference": "thunderbird-locale-bn"},
          {"reference": "thunderbird-locale-bn-bd"},
          {"reference": "thunderbird-locale-br"},
          {"reference": "thunderbird-locale-ca"},
          {"reference": "thunderbird-locale-cak"},
          {"reference": "thunderbird-locale-cs"},
          {"reference": "thunderbird-locale-cy"},
          {"reference": "thunderbird-locale-da"},
          {"reference": "thunderbird-locale-de"},
          {"reference": "thunderbird-locale-dsb"},
          {"reference": "thunderbird-locale-el"},
          {"reference": "thunderbird-locale-en-gb"},
          {"reference": "thunderbird-locale-en-us"},
          {"reference": "thunderbird-locale-es-ar"},
          {"reference": "thunderbird-locale-es-es"},
          {"reference": "thunderbird-locale-fy-nl"},
          {"reference": "thunderbird-locale-ga-ie"},
          {"reference": "thunderbird-locale-nb-no"},
          {"reference": "thunderbird-locale-nn-no"},
          {"reference": "thunderbird-locale-pa-in"},
          {"reference": "thunderbird-locale-pt-br"},
          {"reference": "thunderbird-locale-pt-pt"},
          {"reference": "thunderbird-locale-sv-se"},
          {"reference": "thunderbird-locale-ta-lk"},
          {"reference": "thunderbird-locale-zh-cn"},
          {"reference": "thunderbird-locale-zh-tw"},
          {"reference": "thunderbird-mozsymbols"},
          {"reference": "xul-ext-calendar-timezones"},
          {"reference": "xul-ext-gdata-provider"},
          {"reference": "xul-ext-lightning"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-locale-af"},
          {"reference": "thunderbird-locale-ar"},
          {"reference": "thunderbird-locale-ast"},
          {"reference": "thunderbird-locale-be"},
          {"reference": "thunderbird-locale-bg"},
          {"reference": "thunderbird-locale-bn"},
          {"reference": "thunderbird-locale-bn-bd"},
          {"reference": "thunderbird-locale-br"},
          {"reference": "thunderbird-locale-ca"},
          {"reference": "thunderbird-locale-cak"},
          {"reference": "thunderbird-locale-cs"},
          {"reference": "thunderbird-locale-cy"},
          {"reference": "thunderbird-locale-da"},
          {"reference": "thunderbird-locale-de"},
          {"reference": "thunderbird-locale-dsb"},
          {"reference": "thunderbird-locale-el"},
          {"reference": "thunderbird-locale-en"},
          {"reference": "thunderbird-locale-en-gb"},
          {"reference": "thunderbird-locale-en-us"},
          {"reference": "thunderbird-locale-es"},
          {"reference": "thunderbird-locale-es-ar"},
          {"reference": "thunderbird-locale-es-es"},
          {"reference": "thunderbird-locale-et"},
          {"reference": "thunderbird-locale-eu"},
          {"reference": "thunderbird-locale-fa"},
          {"reference": "thunderbird-locale-fi"},
          {"reference": "thunderbird-locale-fr"},
          {"reference": "thunderbird-locale-fy"},
          {"reference": "thunderbird-locale-fy-nl"},
          {"reference": "thunderbird-locale-ga"},
          {"reference": "thunderbird-locale-ga-ie"},
          {"reference": "thunderbird-locale-gd"},
          {"reference": "thunderbird-locale-gl"},
          {"reference": "thunderbird-locale-he"},
          {"reference": "thunderbird-locale-hr"},
          {"reference": "thunderbird-locale-hsb"},
          {"reference": "thunderbird-locale-hu"},
          {"reference": "thunderbird-locale-hy"},
          {"reference": "thunderbird-locale-id"},
          {"reference": "thunderbird-locale-is"},
          {"reference": "thunderbird-locale-it"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-locale-af"},
          {"reference": "thunderbird-locale-ar"},
          {"reference": "thunderbird-locale-ast"},
          {"reference": "thunderbird-locale-be"},
          {"reference": "thunderbird-locale-bg"},
          {"reference": "thunderbird-locale-bn"},
          {"reference": "thunderbird-locale-bn-bd"},
          {"reference": "thunderbird-locale-br"},
          {"reference": "thunderbird-locale-ca"},
          {"reference": "thunderbird-locale-cak"},
          {"reference": "thunderbird-locale-cs"},
          {"reference": "thunderbird-locale-cy"},
          {"reference": "thunderbird-locale-da"},
          {"reference": "thunderbird-locale-de"},
          {"reference": "thunderbird-locale-dsb"},
          {"reference": "thunderbird-locale-el"},
          {"reference": "thunderbird-locale-en"},
          {"reference": "thunderbird-locale-en-gb"},
          {"reference": "thunderbird-locale-en-us"},
          {"reference": "thunderbird-locale-es"},
          {"reference": "thunderbird-locale-es-ar"},
          {"reference": "thunderbird-locale-es-es"},
          {"reference": "thunderbird-locale-et"},
          {"reference": "thunderbird-locale-eu"},
          {"reference": "thunderbird-locale-fa"},
          {"reference": "thunderbird-locale-fi"},
          {"reference": "thunderbird-locale-fr"},
          {"reference": "thunderbird-locale-fy"},
          {"reference": "thunderbird-locale-fy-nl"},
          {"reference": "thunderbird-locale-ga"},
          {"reference": "thunderbird-locale-ga-ie"},
          {"reference": "thunderbird-locale-gd"},
          {"reference": "thunderbird-locale-gl"},
          {"reference": "thunderbird-locale-he"},
          {"reference": "thunderbird-locale-hr"},
          {"reference": "thunderbird-locale-hsb"},
          {"reference": "thunderbird-locale-hu"},
          {"reference": "thunderbird-locale-hy"},
          {"reference": "thunderbird-locale-id"},
          {"reference": "thunderbird-locale-is"},
          {"reference": "thunderbird-locale-it"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (!empty_or_null(third_party_support)) {
    var third_party_vendors = distro_constraints_values['third_party'];
    if (!empty_or_null(third_party_vendors)) {
        var vendor;
        foreach vendor (third_party_vendors) {
            if (vendor == third_party_support) exit(0, 'A third party management patch is available for this vulnerability from ' + vendor + '.\n');
        }
    }
}

var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}