Linux Distros Unpatched Vulnerability : CVE-2026-26158

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

include('compat.inc');

if (description)
{
  script_id(298799);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/22");

  script_cve_id("CVE-2026-26158");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-26158");

  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.

  - A flaw was found in BusyBox. This vulnerability allows an attacker to modify files outside of the intended
    extraction directory by crafting a malicious tar archive containing unvalidated hardlink or symlink
    entries. If the tar archive is extracted with elevated privileges, this flaw can lead to privilege
    escalation, enabling an attacker to gain unauthorized access to critical system files. (CVE-2026-26158)

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-2026-26158");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-26158");
  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:L/AC:M/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:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-26158");

  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:"2026/02/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/02/12");

  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: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:"p-cpe:/a:canonical:ubuntu_linux:busybox");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:busybox");
  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/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");

  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": "busybox"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "busybox"},
          {"reference": "busybox-initramfs"},
          {"reference": "busybox-static"},
          {"reference": "busybox-syslogd"},
          {"reference": "busybox-udeb"},
          {"reference": "udhcpc"},
          {"reference": "udhcpd"}
        ]
      }
    ]
  }
};

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');
}