Linux Distros Unpatched Vulnerability : CVE-2026-55856

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

include('compat.inc');

if (description)
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  script_id(342406);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/03");

  script_cve_id("CVE-2026-55856");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-55856");

  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.

  - MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases.
    Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, when a Java application connects with sslMode=verify-full or
    sslMode=verify-ca, supplies a password, and does not configure serverSslCert or trustStore, Connector/J
    can accept an untrusted self-signed certificate through the fallbackToSystemTrustStore=true ephemeral
    trust manager and record its certFingerprint for later identity binding. The OK-packet and authentication-
    switch paths enforce the certificate fingerprint, but the initial-handshake path does not.
    HandshakeResponse.encode() can therefore build and send a mysql_clear_password response before checking
    certFingerprint != null && !isMitMProof(), sslMode, or whether the authentication plugin is resistant to a
    man-in-the-middle, and the initial path also bypasses restrictedAuth. An active man-in-the-middle or
    hostile server can present a self-signed certificate, claim to be MariaDB, select mysql_clear_password as
    the initial authentication plugin, and receive the full database password before the connection is
    rejected. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9. (CVE-2026-55856)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2026-55856");
  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:H/Au:N/C:C/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:H/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-2026-55856");

  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:"2026/08/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/02");

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  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/CentOS Linux-8", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9");

  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/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "mariadb-java-client"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "mariadb-java-client"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "Judy"},
          {"reference": "galera"},
          {"reference": "mariadb"},
          {"reference": "mariadb-backup"},
          {"reference": "mariadb-common"},
          {"reference": "mariadb-devel"},
          {"reference": "mariadb-embedded"},
          {"reference": "mariadb-embedded-devel"},
          {"reference": "mariadb-errmsg"},
          {"reference": "mariadb-gssapi-server"},
          {"reference": "mariadb-oqgraph-engine"},
          {"reference": "mariadb-pam"},
          {"reference": "mariadb-server"},
          {"reference": "mariadb-server-galera"},
          {"reference": "mariadb-server-utils"},
          {"reference": "mariadb-test"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "Judy"},
          {"reference": "galera"},
          {"reference": "mariadb"},
          {"reference": "mariadb-backup"},
          {"reference": "mariadb-common"},
          {"reference": "mariadb-devel"},
          {"reference": "mariadb-embedded"},
          {"reference": "mariadb-embedded-devel"},
          {"reference": "mariadb-errmsg"},
          {"reference": "mariadb-gssapi-server"},
          {"reference": "mariadb-oqgraph-engine"},
          {"reference": "mariadb-pam"},
          {"reference": "mariadb-server"},
          {"reference": "mariadb-server-galera"},
          {"reference": "mariadb-server-utils"},
          {"reference": "mariadb-test"}
        ]
      }
    ]
  }
};

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');
}