Linux Distros Unpatched Vulnerability : CVE-2026-34480

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

include('compat.inc');

if (description)
{
  script_id(306043);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/01");

  script_cve_id("CVE-2026-34480");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-34480");

  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.

  - Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in
    versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification
    https://www.w3.org/TR/xml/#charsets producing invalid XML output whenever a log message or MDC value
    contains such characters. The impact depends on the StAX implementation in use: * JRE built-in StAX:
    Forbidden characters are silently written to the output, producing malformed XML. Conforming parsers must
    reject such documents with a fatal error, which may cause downstream log-processing systems to drop the
    affected records. * Alternative StAX implementations (e.g., Woodstox https://github.com/FasterXML/woodstox
    , a transitive dependency of the Jackson XML Dataformat module): An exception is thrown during the logging
    call, and the log event is never delivered to its intended appender, only to Log4j's internal status
    logger. Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue by sanitizing
    forbidden characters before XML output. (CVE-2026-34480)

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-2026-34480");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-34480");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-34480");
  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:N/I:N/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:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-34480");

  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:"2026/04/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  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:25.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:8");
  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:"cpe:/o:redhat:enterprise_linux:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache-log4j1.2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:apache-log4j2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:log4j");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:log4j-jcl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:log4j-slf4j");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:log4j-web");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:apache-log4j1.2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:apache-log4j2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:log4j");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:log4j-jcl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:log4j-slf4j");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:log4j-web");
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  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/CentOS Linux-8", "Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9", "Host/OS/Ubuntu Linux-14.04", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04", "Host/OS/Ubuntu Linux-25.10", "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/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/Debian/dpkg-l")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) 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": "liblog4j1.2-java"},
          {"reference": "liblog4j1.2-java-doc"},
          {"reference": "liblog4j2-java"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "liblog4j1.2-java"},
          {"reference": "liblog4j1.2-java-doc"},
          {"reference": "liblog4j2-java"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "liblog4j1.2-java"},
          {"reference": "liblog4j1.2-java-doc"},
          {"reference": "liblog4j2-java"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "liblog4j1.2-java"},
          {"reference": "liblog4j1.2-java-doc"},
          {"reference": "liblog4j2-java"}
        ]
      }
    ]
  },
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "liblog4j1.2-java"},
          {"reference": "liblog4j1.2-java-doc"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "apache-log4j1.2"},
          {"reference": "apache-log4j2"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "log4j"},
          {"reference": "log4j-jcl"},
          {"reference": "log4j-slf4j"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "log4j"},
          {"reference": "log4j-jcl"},
          {"reference": "log4j-slf4j"},
          {"reference": "log4j-web"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "log4j"},
          {"reference": "log4j-jcl"},
          {"reference": "log4j-slf4j"},
          {"reference": "log4j-web"}
        ]
      }
    ]
  }
};

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 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');
}