Linux Distros Unpatched Vulnerability : CVE-2026-15813

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

include('compat.inc');

if (description)
{
  script_id(327974);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/20");

  script_cve_id("CVE-2026-15813");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-15813");

  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 vulnerability was found in the network packet de-fragmentation engine of kronosnet (Version affected <=
    1.34). The internal reassembly code does not properly validate sequence numbers of incoming payload
    fragments. An attacker can exploit this lack of verification by transmitting malformed packets with
    corrupted sequence parameters. Under specific conditions, this forces the packet processing layer to parse
    data outside the designated bounds of the internal memory structures, causing an out-of-bounds memory
    access or heap corruption. This behavior can result in sudden application crashes or system instability.
    (CVE-2026-15813)

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-2026-15813");
  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: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: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-2026-15813");

  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:"2026/07/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:centos:centos:8");
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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:libknet1");
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  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/Red Hat Enterprise Linux-10", "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/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Red Hat Enterprise Linux-10": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "10",
        "pkgs": [
          {"reference": "libknet1"},
          {"reference": "libknet1-compress-bzip2-plugin"},
          {"reference": "libknet1-compress-lz4-plugin"},
          {"reference": "libknet1-compress-lzma-plugin"},
          {"reference": "libknet1-compress-lzo2-plugin"},
          {"reference": "libknet1-compress-plugins-all"},
          {"reference": "libknet1-compress-zlib-plugin"},
          {"reference": "libknet1-compress-zstd-plugin"},
          {"reference": "libknet1-crypto-nss-plugin"},
          {"reference": "libknet1-crypto-openssl-plugin"},
          {"reference": "libknet1-crypto-plugins-all"},
          {"reference": "libknet1-devel"},
          {"reference": "libknet1-plugins-all"},
          {"reference": "libnozzle1"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "libknet1"},
          {"reference": "libknet1-compress-bzip2-plugin"},
          {"reference": "libknet1-compress-lz4-plugin"},
          {"reference": "libknet1-compress-lzma-plugin"},
          {"reference": "libknet1-compress-lzo2-plugin"},
          {"reference": "libknet1-compress-plugins-all"},
          {"reference": "libknet1-compress-zlib-plugin"},
          {"reference": "libknet1-compress-zstd-plugin"},
          {"reference": "libknet1-crypto-nss-plugin"},
          {"reference": "libknet1-crypto-openssl-plugin"},
          {"reference": "libknet1-crypto-plugins-all"},
          {"reference": "libknet1-devel"},
          {"reference": "libknet1-plugins-all"},
          {"reference": "libnozzle1"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "libknet1"},
          {"reference": "libknet1-compress-bzip2-plugin"},
          {"reference": "libknet1-compress-lz4-plugin"},
          {"reference": "libknet1-compress-lzma-plugin"},
          {"reference": "libknet1-compress-lzo2-plugin"},
          {"reference": "libknet1-compress-plugins-all"},
          {"reference": "libknet1-compress-zlib-plugin"},
          {"reference": "libknet1-crypto-nss-plugin"},
          {"reference": "libknet1-crypto-openssl-plugin"},
          {"reference": "libknet1-crypto-plugins-all"},
          {"reference": "libknet1-devel"},
          {"reference": "libknet1-plugins-all"},
          {"reference": "libnozzle1"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "libknet1"},
          {"reference": "libknet1-compress-bzip2-plugin"},
          {"reference": "libknet1-compress-lz4-plugin"},
          {"reference": "libknet1-compress-lzma-plugin"},
          {"reference": "libknet1-compress-lzo2-plugin"},
          {"reference": "libknet1-compress-plugins-all"},
          {"reference": "libknet1-compress-zlib-plugin"},
          {"reference": "libknet1-crypto-nss-plugin"},
          {"reference": "libknet1-crypto-openssl-plugin"},
          {"reference": "libknet1-crypto-plugins-all"},
          {"reference": "libknet1-devel"},
          {"reference": "libknet1-plugins-all"},
          {"reference": "libnozzle1"}
        ]
      }
    ]
  }
};

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');
}