Linux Distros Unpatched Vulnerability : CVE-2026-6949

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

include('compat.inc');

if (description)
{
  script_id(330483);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/29");

  script_cve_id("CVE-2026-6949");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-6949");

  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.

  - To calculate the size of a DNS packet region signed by a TSIG record, Samba's internal DNS server
    subtracted the presumed size of the TSIG record. In cases where the record used name compression, an
    incorrect calculation could be made. Usually this manifests as a signing failure, but in extreme cases the
    TSIG record was assumed to be bigger than the entire packet, wrapping the presumed size of the signed
    portion to a very large integer. Efforts to copy this portion inevitably hit unallocated memory.
    (CVE-2026-6949)

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-2026-6949");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-6949");
  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:N/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-2026-6949");

  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:"2026/07/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/29");

  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: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:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:samba");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:samba");
  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-14", "Host/OS/Ubuntu Linux-14.04", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04");

  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/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "ctdb"},
          {"reference": "ldb-tools"},
          {"reference": "libldb-dev"},
          {"reference": "libldb2"},
          {"reference": "libnss-winbind"},
          {"reference": "libpam-winbind"},
          {"reference": "libsmbclient"},
          {"reference": "libsmbclient-dev"},
          {"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": "smbclient"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "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-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"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "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": "smbclient"},
          {"reference": "tdb-tools"},
          {"reference": "winbind"}
        ]
      }
    ]
  },
  "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"}
        ]
      }
    ]
  }
};

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');
}