Linux Distros Unpatched Vulnerability : CVE-2026-15779

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

include('compat.inc');

if (description)
{
  script_id(327209);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/16");

  script_cve_id("CVE-2026-15779");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-15779");

  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 samba's pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target
    account's home directory without validating the path is not a critical system directory such as /. On
    affected systems, accounts with / as their home directory (a common default for system accounts) can have
    this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands
    as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo,
    and package-manager failures). The change does not grant write access to / (which ships with restrictive
    0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation.
    (CVE-2026-15779)

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-2026-15779");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-15779");
  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:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/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-2026-15779");

  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:"2026/07/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/16");

  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:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:7");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:8");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:7");
  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:samba");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:samba-winbind");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:samba-winbind");
  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/CentOS Linux-7", "Host/OS/CentOS Linux-8", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-7", "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-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 = {
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "libnss-winbind"},
          {"reference": "libpam-smbpass"},
          {"reference": "libpam-winbind"},
          {"reference": "libparse-pidl-perl"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libsmbsharemodes-dev"},
          {"reference": "libsmbsharemodes0"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dbg"},
          {"reference": "samba-dev"},
          {"reference": "samba-doc"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libparse-pidl-perl"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dbg"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libparse-pidl-perl"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python3-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python3-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "ldb-tools"},
          {"reference": "libldb-dev"},
          {"reference": "libldb2"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libsmbclient0"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python3-ldb"},
          {"reference": "python3-ldb-dev"},
          {"reference": "python3-samba"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-ad-dc"},
          {"reference": "samba-ad-provision"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-modules"},
          {"reference": "samba-vfs-modules-extra"},
          {"reference": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "ldb-tools"},
          {"reference": "libldb-dev"},
          {"reference": "libldb2"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"reference": "libsmbclient0"},
          {"reference": "libtalloc-dev"},
          {"reference": "libtalloc2"},
          {"reference": "libtdb-dev"},
          {"reference": "libtdb1"},
          {"reference": "libtevent-dev"},
          {"reference": "libtevent0"},
          {"reference": "libtevent0t64"},
          {"reference": "libwbclient-dev"},
          {"reference": "libwbclient0"},
          {"reference": "python3-ldb"},
          {"reference": "python3-samba"},
          {"reference": "python3-talloc"},
          {"reference": "python3-tdb"},
          {"reference": "registry-tools"},
          {"reference": "samba"},
          {"reference": "samba-ad-dc"},
          {"reference": "samba-ad-provision"},
          {"reference": "samba-common"},
          {"reference": "samba-common-bin"},
          {"reference": "samba-dev"},
          {"reference": "samba-dsdb-modules"},
          {"reference": "samba-libs"},
          {"reference": "samba-testsuite"},
          {"reference": "samba-vfs-ceph"},
          {"reference": "samba-vfs-glusterfs"},
          {"reference": "samba-vfs-modules"},
          {"reference": "samba-vfs-modules-extra"},
          {"reference": "smbclient"},
          {"reference": "tdb-tools"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "CentOS Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "samba-winbind"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "samba-winbind"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "samba-winbind"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "samba-winbind"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "samba-winbind"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "samba-winbind"}
        ]
      }
    ]
  }
};

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');
}