Linux Distros Unpatched Vulnerability : CVE-2026-24401

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

include('compat.inc');

if (description)
{
  script_id(296504);
  script_version("1.8");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/25");

  script_cve_id("CVE-2026-24401");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-24401");

  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.

  - Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol
    suite. In versions 0.9rc2 and below, avahi-daemon can be crashed via a segmentation fault by sending an
    unsolicited mDNS response containing a recursive CNAME record, where the alias and canonical name point to
    the same domain (e.g., h.local as a CNAME for h.local). This causes unbounded recursion in the
    lookup_handle_cname function, leading to stack exhaustion. The vulnerability affects record browsers where
    AVAHI_LOOKUP_USE_MULTICAST is set explicitly, which includes record browsers created by resolvers used by
    nss-mdns. This issue is patched in commit 78eab31128479f06e30beb8c1cbf99dd921e2524. (CVE-2026-24401)

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-2026-24401");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-24401");
  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: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:R/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-2026-24401");

  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:"2026/01/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/24");

  script_set_attribute(attribute:"plugin_type", value:"local");
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  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:enterprise_linux:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-autoipd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-compat-howl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-compat-howl-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-compat-libdns_sd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-compat-libdns_sd-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-dnsconfd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-glib");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-glib-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-gobject");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:avahi-gobject-devel");
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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-7", "Host/OS/CentOS Linux-8", "Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Red Hat Enterprise Linux-10", "Host/OS/Red Hat Enterprise Linux-6", "Host/OS/Red Hat Enterprise Linux-7", "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/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": "avahi-autoipd"},
          {"reference": "avahi-daemon"},
          {"reference": "avahi-discover"},
          {"reference": "avahi-dnsconfd"},
          {"reference": "avahi-ui-utils"},
          {"reference": "avahi-utils"},
          {"reference": "gir1.2-avahi-0.6"},
          {"reference": "libavahi-client-dev"},
          {"reference": "libavahi-client3"},
          {"reference": "libavahi-common-data"},
          {"reference": "libavahi-common-dev"},
          {"reference": "libavahi-common3"},
          {"reference": "libavahi-compat-libdnssd-dev"},
          {"reference": "libavahi-compat-libdnssd1"},
          {"reference": "libavahi-core-dev"},
          {"reference": "libavahi-core7"},
          {"reference": "libavahi-glib-dev"},
          {"reference": "libavahi-glib1"},
          {"reference": "libavahi-gobject-dev"},
          {"reference": "libavahi-gobject0"},
          {"reference": "libavahi-ui-gtk3-0"},
          {"reference": "libavahi-ui-gtk3-dev"},
          {"reference": "python3-avahi"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-daemon"},
          {"reference": "avahi-discover"},
          {"reference": "avahi-dnsconfd"},
          {"reference": "avahi-ui-utils"},
          {"reference": "avahi-utils"},
          {"reference": "gir1.2-avahi-0.6"},
          {"reference": "libavahi-client-dev"},
          {"reference": "libavahi-client3"},
          {"reference": "libavahi-common-data"},
          {"reference": "libavahi-common-dev"},
          {"reference": "libavahi-common3"},
          {"reference": "libavahi-compat-libdnssd-dev"},
          {"reference": "libavahi-compat-libdnssd1"},
          {"reference": "libavahi-core-dev"},
          {"reference": "libavahi-core7"},
          {"reference": "libavahi-glib-dev"},
          {"reference": "libavahi-glib1"},
          {"reference": "libavahi-gobject-dev"},
          {"reference": "libavahi-gobject0"},
          {"reference": "libavahi-ui-gtk3-0"},
          {"reference": "libavahi-ui-gtk3-dev"},
          {"reference": "python3-avahi"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-daemon"},
          {"reference": "avahi-discover"},
          {"reference": "avahi-dnsconfd"},
          {"reference": "avahi-ui-utils"},
          {"reference": "avahi-utils"},
          {"reference": "gir1.2-avahi-0.6"},
          {"reference": "libavahi-client-dev"},
          {"reference": "libavahi-client3"},
          {"reference": "libavahi-common-data"},
          {"reference": "libavahi-common-dev"},
          {"reference": "libavahi-common3"},
          {"reference": "libavahi-compat-libdnssd-dev"},
          {"reference": "libavahi-compat-libdnssd1"},
          {"reference": "libavahi-core-dev"},
          {"reference": "libavahi-core7"},
          {"reference": "libavahi-glib-dev"},
          {"reference": "libavahi-glib1"},
          {"reference": "libavahi-gobject-dev"},
          {"reference": "libavahi-gobject0"},
          {"reference": "libavahi-ui-gtk3-0"},
          {"reference": "libavahi-ui-gtk3-dev"},
          {"reference": "python3-avahi"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-tools"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-6": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "6",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-dnsconfd"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-gobject"},
          {"reference": "avahi-gobject-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-qt3"},
          {"reference": "avahi-qt3-devel"},
          {"reference": "avahi-qt4"},
          {"reference": "avahi-qt4-devel"},
          {"reference": "avahi-tools"},
          {"reference": "avahi-ui"},
          {"reference": "avahi-ui-devel"},
          {"reference": "avahi-ui-tools"}
        ]
      }
    ]
  },
  "CentOS Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-dnsconfd"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-gobject"},
          {"reference": "avahi-gobject-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-qt3"},
          {"reference": "avahi-qt3-devel"},
          {"reference": "avahi-qt4"},
          {"reference": "avahi-qt4-devel"},
          {"reference": "avahi-tools"},
          {"reference": "avahi-ui"},
          {"reference": "avahi-ui-devel"},
          {"reference": "avahi-ui-gtk3"},
          {"reference": "avahi-ui-tools"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-7": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "7",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-dnsconfd"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-gobject"},
          {"reference": "avahi-gobject-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-qt3"},
          {"reference": "avahi-qt3-devel"},
          {"reference": "avahi-qt4"},
          {"reference": "avahi-qt4-devel"},
          {"reference": "avahi-tools"},
          {"reference": "avahi-ui"},
          {"reference": "avahi-ui-devel"},
          {"reference": "avahi-ui-gtk3"},
          {"reference": "avahi-ui-tools"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-gobject"},
          {"reference": "avahi-gobject-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-tools"},
          {"reference": "avahi-ui"},
          {"reference": "avahi-ui-devel"},
          {"reference": "avahi-ui-gtk3"},
          {"reference": "python3-avahi"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-gobject"},
          {"reference": "avahi-gobject-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-tools"},
          {"reference": "avahi-ui"},
          {"reference": "avahi-ui-devel"},
          {"reference": "avahi-ui-gtk3"},
          {"reference": "python3-avahi"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "avahi"},
          {"reference": "avahi-autoipd"},
          {"reference": "avahi-compat-howl"},
          {"reference": "avahi-compat-howl-devel"},
          {"reference": "avahi-compat-libdns_sd"},
          {"reference": "avahi-compat-libdns_sd-devel"},
          {"reference": "avahi-devel"},
          {"reference": "avahi-glib"},
          {"reference": "avahi-glib-devel"},
          {"reference": "avahi-gobject"},
          {"reference": "avahi-gobject-devel"},
          {"reference": "avahi-libs"},
          {"reference": "avahi-tools"}
        ]
      }
    ]
  }
};

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_NOTE,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}