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Linux Distros Unpatched Vulnerability : CVE-2026-14899

🗓️ 26 Jul 2026 00:00:00Reported by TenableType 
nessus
 nessus🔗 www.tenable.com👁 5 Views

Unpatched Linux packages expose Thunderbird mail header parsing off-by-one bug that may crash.

Related
Refs
Code
ReporterTitlePublishedViews
Family
ATTACKERKB		CVE-2026-14899
22 Jul 202619:19
–attackerkb
Circl		CVE-2026-14899
24 Jul 202600:01
–circl
CVE		CVE-2026-14899
22 Jul 202619:19
–cve
Cvelist		CVE-2026-14899 Off-by-one out of bounds read in MIME header parser for forwarding
22 Jul 202619:19
–cvelist
Debian CVE		CVE-2026-14899
22 Jul 202619:19
–debiancve
EUVD		EUVD-2026-47773
22 Jul 202619:19
–euvd
Kaspersky		KLA91169 Multiple vulnerabilities in Mozilla Thunderbird ESR
21 Jul 202600:00
–kaspersky
Tenable Nessus		Mozilla Thunderbird < 140.13
22 Jul 202600:00
–nessus
Tenable Nessus		Mozilla Thunderbird < 153.0
22 Jul 202600:00
–nessus
Tenable Nessus		Mozilla Thunderbird < 140.13
22 Jul 202600:00
–nessus
Rows per page
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(330016);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/26");

  script_cve_id("CVE-2026-14899");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-14899");

  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 code to parse MIME headers for display when forwarding a message (if the setting to view all headers
    was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer
    for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and
    Thunderbird 140.13. (CVE-2026-14899)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-14899");
  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:M/Au:N/C:P/I:N/A:N");
  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-2026-14899");

  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:"2026/07/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/26");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_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/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14");

  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 = {
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-l10n-af"},
          {"reference": "thunderbird-l10n-all"},
          {"reference": "thunderbird-l10n-ar"},
          {"reference": "thunderbird-l10n-ast"},
          {"reference": "thunderbird-l10n-be"},
          {"reference": "thunderbird-l10n-bg"},
          {"reference": "thunderbird-l10n-br"},
          {"reference": "thunderbird-l10n-ca"},
          {"reference": "thunderbird-l10n-cak"},
          {"reference": "thunderbird-l10n-cs"},
          {"reference": "thunderbird-l10n-cy"},
          {"reference": "thunderbird-l10n-da"},
          {"reference": "thunderbird-l10n-de"},
          {"reference": "thunderbird-l10n-dsb"},
          {"reference": "thunderbird-l10n-el"},
          {"reference": "thunderbird-l10n-en-ca"},
          {"reference": "thunderbird-l10n-en-gb"},
          {"reference": "thunderbird-l10n-es-ar"},
          {"reference": "thunderbird-l10n-es-es"},
          {"reference": "thunderbird-l10n-es-mx"},
          {"reference": "thunderbird-l10n-et"},
          {"reference": "thunderbird-l10n-eu"},
          {"reference": "thunderbird-l10n-fi"},
          {"reference": "thunderbird-l10n-fr"},
          {"reference": "thunderbird-l10n-fy-nl"},
          {"reference": "thunderbird-l10n-ga-ie"},
          {"reference": "thunderbird-l10n-gd"},
          {"reference": "thunderbird-l10n-gl"},
          {"reference": "thunderbird-l10n-he"},
          {"reference": "thunderbird-l10n-hr"},
          {"reference": "thunderbird-l10n-hsb"},
          {"reference": "thunderbird-l10n-hu"},
          {"reference": "thunderbird-l10n-hy-am"},
          {"reference": "thunderbird-l10n-id"},
          {"reference": "thunderbird-l10n-is"},
          {"reference": "thunderbird-l10n-it"},
          {"reference": "thunderbird-l10n-ja"},
          {"reference": "thunderbird-l10n-ka"},
          {"reference": "thunderbird-l10n-kab"},
          {"reference": "thunderbird-l10n-kk"},
          {"reference": "thunderbird-l10n-ko"},
          {"reference": "thunderbird-l10n-lt"},
          {"reference": "thunderbird-l10n-lv"},
          {"reference": "thunderbird-l10n-ms"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-l10n-af"},
          {"reference": "thunderbird-l10n-all"},
          {"reference": "thunderbird-l10n-ar"},
          {"reference": "thunderbird-l10n-ast"},
          {"reference": "thunderbird-l10n-be"},
          {"reference": "thunderbird-l10n-bg"},
          {"reference": "thunderbird-l10n-br"},
          {"reference": "thunderbird-l10n-ca"},
          {"reference": "thunderbird-l10n-cak"},
          {"reference": "thunderbird-l10n-cs"},
          {"reference": "thunderbird-l10n-cy"},
          {"reference": "thunderbird-l10n-da"},
          {"reference": "thunderbird-l10n-de"},
          {"reference": "thunderbird-l10n-dsb"},
          {"reference": "thunderbird-l10n-el"},
          {"reference": "thunderbird-l10n-en-ca"},
          {"reference": "thunderbird-l10n-en-gb"},
          {"reference": "thunderbird-l10n-es-ar"},
          {"reference": "thunderbird-l10n-es-es"},
          {"reference": "thunderbird-l10n-es-mx"},
          {"reference": "thunderbird-l10n-et"},
          {"reference": "thunderbird-l10n-eu"},
          {"reference": "thunderbird-l10n-fi"},
          {"reference": "thunderbird-l10n-fr"},
          {"reference": "thunderbird-l10n-fy-nl"},
          {"reference": "thunderbird-l10n-ga-ie"},
          {"reference": "thunderbird-l10n-gd"},
          {"reference": "thunderbird-l10n-gl"},
          {"reference": "thunderbird-l10n-he"},
          {"reference": "thunderbird-l10n-hr"},
          {"reference": "thunderbird-l10n-hsb"},
          {"reference": "thunderbird-l10n-hu"},
          {"reference": "thunderbird-l10n-hy-am"},
          {"reference": "thunderbird-l10n-id"},
          {"reference": "thunderbird-l10n-is"},
          {"reference": "thunderbird-l10n-it"},
          {"reference": "thunderbird-l10n-ja"},
          {"reference": "thunderbird-l10n-ka"},
          {"reference": "thunderbird-l10n-kab"},
          {"reference": "thunderbird-l10n-kk"},
          {"reference": "thunderbird-l10n-ko"},
          {"reference": "thunderbird-l10n-lt"},
          {"reference": "thunderbird-l10n-lv"},
          {"reference": "thunderbird-l10n-ms"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-l10n-af"},
          {"reference": "thunderbird-l10n-all"},
          {"reference": "thunderbird-l10n-ar"},
          {"reference": "thunderbird-l10n-ast"},
          {"reference": "thunderbird-l10n-be"},
          {"reference": "thunderbird-l10n-bg"},
          {"reference": "thunderbird-l10n-br"},
          {"reference": "thunderbird-l10n-ca"},
          {"reference": "thunderbird-l10n-cak"},
          {"reference": "thunderbird-l10n-cs"},
          {"reference": "thunderbird-l10n-cy"},
          {"reference": "thunderbird-l10n-da"},
          {"reference": "thunderbird-l10n-de"},
          {"reference": "thunderbird-l10n-dsb"},
          {"reference": "thunderbird-l10n-el"},
          {"reference": "thunderbird-l10n-en-ca"},
          {"reference": "thunderbird-l10n-en-gb"},
          {"reference": "thunderbird-l10n-es-ar"},
          {"reference": "thunderbird-l10n-es-es"},
          {"reference": "thunderbird-l10n-es-mx"},
          {"reference": "thunderbird-l10n-et"},
          {"reference": "thunderbird-l10n-eu"},
          {"reference": "thunderbird-l10n-fi"},
          {"reference": "thunderbird-l10n-fr"},
          {"reference": "thunderbird-l10n-fy-nl"},
          {"reference": "thunderbird-l10n-ga-ie"},
          {"reference": "thunderbird-l10n-gd"},
          {"reference": "thunderbird-l10n-gl"},
          {"reference": "thunderbird-l10n-he"},
          {"reference": "thunderbird-l10n-hr"},
          {"reference": "thunderbird-l10n-hsb"},
          {"reference": "thunderbird-l10n-hu"},
          {"reference": "thunderbird-l10n-hy-am"},
          {"reference": "thunderbird-l10n-id"},
          {"reference": "thunderbird-l10n-is"},
          {"reference": "thunderbird-l10n-it"},
          {"reference": "thunderbird-l10n-ja"},
          {"reference": "thunderbird-l10n-ka"},
          {"reference": "thunderbird-l10n-kab"},
          {"reference": "thunderbird-l10n-kk"},
          {"reference": "thunderbird-l10n-ko"},
          {"reference": "thunderbird-l10n-lt"},
          {"reference": "thunderbird-l10n-lv"},
          {"reference": "thunderbird-l10n-ms"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "thunderbird"},
          {"reference": "thunderbird-l10n-af"},
          {"reference": "thunderbird-l10n-all"},
          {"reference": "thunderbird-l10n-ar"},
          {"reference": "thunderbird-l10n-ast"},
          {"reference": "thunderbird-l10n-be"},
          {"reference": "thunderbird-l10n-bg"},
          {"reference": "thunderbird-l10n-br"},
          {"reference": "thunderbird-l10n-ca"},
          {"reference": "thunderbird-l10n-cak"},
          {"reference": "thunderbird-l10n-cs"},
          {"reference": "thunderbird-l10n-cy"},
          {"reference": "thunderbird-l10n-da"},
          {"reference": "thunderbird-l10n-de"},
          {"reference": "thunderbird-l10n-dsb"},
          {"reference": "thunderbird-l10n-el"},
          {"reference": "thunderbird-l10n-en-ca"},
          {"reference": "thunderbird-l10n-en-gb"},
          {"reference": "thunderbird-l10n-es-ar"},
          {"reference": "thunderbird-l10n-es-es"},
          {"reference": "thunderbird-l10n-es-mx"},
          {"reference": "thunderbird-l10n-et"},
          {"reference": "thunderbird-l10n-eu"},
          {"reference": "thunderbird-l10n-fi"},
          {"reference": "thunderbird-l10n-fr"},
          {"reference": "thunderbird-l10n-fy-nl"},
          {"reference": "thunderbird-l10n-ga-ie"},
          {"reference": "thunderbird-l10n-gd"},
          {"reference": "thunderbird-l10n-gl"},
          {"reference": "thunderbird-l10n-he"},
          {"reference": "thunderbird-l10n-hr"},
          {"reference": "thunderbird-l10n-hsb"},
          {"reference": "thunderbird-l10n-hu"},
          {"reference": "thunderbird-l10n-hy-am"},
          {"reference": "thunderbird-l10n-id"},
          {"reference": "thunderbird-l10n-is"},
          {"reference": "thunderbird-l10n-it"},
          {"reference": "thunderbird-l10n-ja"},
          {"reference": "thunderbird-l10n-ka"},
          {"reference": "thunderbird-l10n-kab"},
          {"reference": "thunderbird-l10n-kk"},
          {"reference": "thunderbird-l10n-ko"},
          {"reference": "thunderbird-l10n-lt"},
          {"reference": "thunderbird-l10n-lv"},
          {"reference": "thunderbird-l10n-ms"}
        ]
      }
    ]
  }
};

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');
}

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26 Jul 2026 00:00Current
5.9Medium risk
Vulners AI Score5.9
EPSS0.00142
unpatched vulnerabilitylinux packagesmail header parsingoff by onethunderbird crashcve-2026-14899
5