Linux Distros Unpatched Vulnerability : CVE-2026-98432

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

include('compat.inc');

if (description)
{
  script_id(366212);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/15");

  script_cve_id("CVE-2026-98432");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-98432");

  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.

  - ipv4: free inet_opt and ireq_opt after an RCU grace period tcp_v4_syn_recv_sock() transfers ownership of
    ireq->ireq_opt to the child socket (newinet->inet_opt) without copying it. Another cpu can concurrently
    process a retransmitted SYN for the same request socket, and send a SYNACK from tcp_check_req().
    tcp_v4_send_synack() and inet_csk_route_req() read ireq->ireq_opt under rcu_read_lock() only, and
    ip_build_and_send_pkt() and ip_options_build() then read opt->optlen twice. Note that the SYNACK timer
    itself is not an issue: it holds a reference on its request socket, and inet_csk_reqsk_queue_drop() calls
    timer_delete_sync() before the child can be freed. Since commit 079096f103fa (tcp/dccp: install syn_recv
    requests into ehash table), request sockets are processed without holding the listener lock, so nothing
    prevents the child socket from being freed while the SYNACK is still being built. TCP child sockets do not
    have SOCK_RCU_FREE, and inet_sock_destruct() frees inet_opt with a plain kfree(), leading to a use-after-
    free in ip_options_build(). A similar issue exists with request socket migration
    (net.ipv4.tcp_migrate_req=1, or a BPF_SK_REUSEPORT_SELECT_OR_MIGRATE program). reqsk_timer_handler()
    clones the request socket with inet_reqsk_clone(), so that the old request socket and its clone share the
    same ireq_opt, then reqsk_migrate_reset() clears the pointer in the old one. Another cpu holding a
    reference on the old request socket can still be using these options (sending a SYNACK, or creating a
    child in tcp_v4_syn_recv_sock()) when the clone is freed, and tcp_v4_reqsk_destructor() also uses a plain
    kfree(). Readers already use RCU, and other paths replacing inet_opt (do_ip_setsockopt(),
    cipso_v4_sock_setattr()...) already use kfree_rcu(). Use kfree_rcu() in inet_sock_destruct() and
    tcp_v4_reqsk_destructor() as well. IPv6 is not affected by the first issue, because tcp_v6_syn_recv_sock()
    duplicates the options. tcp_v6_reqsk_destructor() has the same migration issue with ipv6_opt, which is
    only set by CALIPSO. This will be addressed in a separate patch. (CVE-2026-98432)

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-2026-98432");
  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: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-2026-98432");

  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:"2026/10/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/15");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:linux");
  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-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14");

  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": "btrfs-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "cdrom-core-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "ext4-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "fat-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "isofs-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "jfs-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "kernel-image-6.1.0-50-alpha-generic-di"},
          {"reference": "linux-doc"},
          {"reference": "linux-doc-6.1"},
          {"reference": "linux-headers-6.1.0"},
          {"reference": "linux-source"},
          {"reference": "linux-source-6.1"},
          {"reference": "linux-support-6.1.0"},
          {"reference": "loop-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "nic-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "nic-shared-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "nic-wireless-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "pata-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "ppp-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "scsi-core-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "scsi-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "scsi-nic-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "serial-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "usb-serial-modules-6.1.0-50-alpha-generic-di"},
          {"reference": "xfs-modules-6.1.0-50-alpha-generic-di"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "bpftool"},
          {"reference": "hyperv-daemons"},
          {"reference": "intel-sdsi"},
          {"reference": "libcpupower-dev"},
          {"reference": "libcpupower1"},
          {"reference": "linux-base-7.2.9+deb14-alpha-generic"},
          {"reference": "linux-base-7.2.9+deb14-amd64"},
          {"reference": "linux-base-7.2.9+deb14-arm64"},
          {"reference": "linux-base-7.2.9+deb14-arm64-16k"},
          {"reference": "linux-base-7.2.9+deb14-armmp"},
          {"reference": "linux-base-7.2.9+deb14-armmp-lpae"},
          {"reference": "linux-base-7.2.9+deb14-cloud-amd64"},
          {"reference": "linux-base-7.2.9+deb14-cloud-arm64"},
          {"reference": "linux-base-7.2.9+deb14-loong64"},
          {"reference": "linux-base-7.2.9+deb14-m68k"},
          {"reference": "linux-base-7.2.9+deb14-parisc"},
          {"reference": "linux-base-7.2.9+deb14-parisc64"},
          {"reference": "linux-base-7.2.9+deb14-powerpc"},
          {"reference": "linux-base-7.2.9+deb14-powerpc64"},
          {"reference": "linux-base-7.2.9+deb14-powerpc64-64k"},
          {"reference": "linux-base-7.2.9+deb14-powerpc64le"},
          {"reference": "linux-base-7.2.9+deb14-powerpc64le-64k"},
          {"reference": "linux-base-7.2.9+deb14-riscv64"},
          {"reference": "linux-base-7.2.9+deb14-rt-amd64"},
          {"reference": "linux-base-7.2.9+deb14-rt-arm64"},
          {"reference": "linux-base-7.2.9+deb14-s390x"},
          {"reference": "linux-base-7.2.9+deb14-sh7751r"},
          {"reference": "linux-base-7.2.9+deb14-sparc64"},
          {"reference": "linux-base-7.2.9+deb14-test"},
          {"reference": "linux-base-alpha-generic"},
          {"reference": "linux-base-armmp"},
          {"reference": "linux-base-armmp-lpae"},
          {"reference": "linux-base-loong64"},
          {"reference": "linux-base-m68k"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "bpftool"},
          {"reference": "hyperv-daemons"},
          {"reference": "intel-sdsi"},
          {"reference": "libcpupower-dev"},
          {"reference": "libcpupower1"},
          {"reference": "linux-bpf-dev"},
          {"reference": "linux-config-6.12"},
          {"reference": "linux-cpupower"},
          {"reference": "linux-doc"},
          {"reference": "linux-doc-6.12"},
          {"reference": "linux-headers-4kc-malta"},
          {"reference": "linux-headers-5kc-malta"},
          {"reference": "linux-headers-6.12.107+deb13-4kc-malta"},
          {"reference": "linux-headers-6.12.107+deb13-5kc-malta"},
          {"reference": "linux-headers-6.12.107+deb13-alpha-generic"},
          {"reference": "linux-headers-6.12.107+deb13-alpha-smp"},
          {"reference": "linux-headers-6.12.107+deb13-amd64"},
          {"reference": "linux-headers-6.12.107+deb13-arm64"},
          {"reference": "linux-headers-6.12.107+deb13-arm64-16k"},
          {"reference": "linux-headers-6.12.107+deb13-armmp"},
          {"reference": "linux-headers-6.12.107+deb13-armmp-lpae"},
          {"reference": "linux-headers-6.12.107+deb13-cloud-amd64"},
          {"reference": "linux-headers-6.12.107+deb13-cloud-arm64"},
          {"reference": "linux-headers-6.12.107+deb13-common"},
          {"reference": "linux-headers-6.12.107+deb13-common-rt"},
          {"reference": "linux-headers-6.12.107+deb13-loong64"},
          {"reference": "linux-headers-6.12.107+deb13-loongson-3"},
          {"reference": "linux-headers-6.12.107+deb13-m68k"},
          {"reference": "linux-headers-6.12.107+deb13-mips32r2eb"},
          {"reference": "linux-headers-6.12.107+deb13-mips32r2el"},
          {"reference": "linux-headers-6.12.107+deb13-mips64r2eb"}
        ]
      }
    ]
  }
};

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');
}