Linux Distros Unpatched Vulnerability : CVE-2026-99288

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

include('compat.inc');

if (description)
{
  script_id(378558);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/10");

  script_cve_id("CVE-2026-99288");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-99288");

  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.

  - inet: reject unhashed sockets during established lookups TCP established ehash lookups are lockless. The
    socket caches involved use SLAB_TYPESAFE_BY_RCU, so memory can be reused before an RCU reader that
    retained its old address has finished. After a tuple match, __inet_lookup_established() and
    __inet6_lookup_established() acquire a reference and repeat the tuple check. They do not check whether the
    new object is hashed. If the address is reused for a socket with the same tuple, the lookup can acquire a
    reference to the new object and return it while its nulls node is unhashed. A PoC that drives reuse with a
    SYN cookie request socket reproduced the crash. The new request socket is unhashed and has a NULL
    rsk_listener. A lookup that had loaded the address of the old request socket acquired the reference
    published by tcp_get_cookie_sock() and returned the new object. tcp_v4_rcv() then read sk_state through
    the NULL listener. The resulting crash was: BUG: kernel NULL pointer dereference, address:
    0000000000000012 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page ...
    Oops: Oops: 0000 [#1] SMP NOPTI CPU: 4 UID: 0 PID: 0 Comm: swapper/4 Not tainted 7.3.0-00591-g0e135910deec
    #1 PREEMPT(lazy) ... RIP: 0010:tcp_v4_rcv+0x44e/0x1280 ... R10: 0000000000000001 R11: 00000000024ca8c0
    R12: 0000000000000000 ... CR2: 0000000000000012 CR3: 0000000103d50004 CR4: 0000000000770ef0 ... Call
    Trace: <IRQ> ? raw_local_deliver+0xae/0x240 ip_protocol_deliver_rcu+0x2d/0x180
    ip_local_deliver_finish+0x84/0x100 ip_sublist_rcv_finish+0x5f/0x70 ip_sublist_rcv+0x12a/0x1d0
    ip_list_rcv+0xfd/0x130 __netif_receive_skb_list_core+0x223/0x250
    netif_receive_skb_list_internal+0x1d2/0x2c0 ? try_fill_recv+0x39/0x7b0 napi_complete_done+0x74/0x170
    virtnet_poll+0x445/0x600 __napi_poll+0x27/0x1e0 net_rx_action+0x2fe/0x3b0 handle_softirqs+0xc2/0x2c0
    __irq_exit_rcu+0x74/0xd0 common_interrupt+0x7f/0x90 </IRQ> ... Kernel panic - not syncing: Fatal exception
    in interrupt After taking a reference, check whether the nulls node is unhashed in both IPv4 and IPv6
    established lookups. If it is unhashed or the tuple no longer matches, drop the reference and restart the
    lookup. Lookups racing with the TIME_WAIT hashdance, or with a request being replaced by its child, now
    restart and find the new socket instead of returning the old one. Request sockets that were never inserted
    into ehash can have a nonzero refcount, and a stale lookup can hold a transient reference. Therefore, when
    SYN cookie, Fast Open, and request migration paths fail after setting a nonzero refcount, release the
    references held by those paths with reqsk_put() instead of freeing the request directly. (CVE-2026-99288)

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-2026-99288");
  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-2026-99288");

  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:"2026/11/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/11/10");

  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-7.2.15+deb14-alpha-generic"},
          {"reference": "linux-base-7.2.15+deb14-amd64"},
          {"reference": "linux-base-7.2.15+deb14-arm64"},
          {"reference": "linux-base-7.2.15+deb14-arm64-16k"},
          {"reference": "linux-base-7.2.15+deb14-armmp"},
          {"reference": "linux-base-7.2.15+deb14-armmp-lpae"},
          {"reference": "linux-base-7.2.15+deb14-cloud-amd64"},
          {"reference": "linux-base-7.2.15+deb14-cloud-arm64"},
          {"reference": "linux-base-7.2.15+deb14-loong64"},
          {"reference": "linux-base-7.2.15+deb14-m68k"},
          {"reference": "linux-base-7.2.15+deb14-parisc"},
          {"reference": "linux-base-7.2.15+deb14-parisc64"},
          {"reference": "linux-base-7.2.15+deb14-powerpc"},
          {"reference": "linux-base-7.2.15+deb14-powerpc64"},
          {"reference": "linux-base-7.2.15+deb14-powerpc64-64k"},
          {"reference": "linux-base-7.2.15+deb14-powerpc64le"},
          {"reference": "linux-base-7.2.15+deb14-powerpc64le-64k"},
          {"reference": "linux-base-7.2.15+deb14-riscv64"},
          {"reference": "linux-base-7.2.15+deb14-rt-amd64"},
          {"reference": "linux-base-7.2.15+deb14-rt-arm64"},
          {"reference": "linux-base-7.2.15+deb14-s390x"},
          {"reference": "linux-base-7.2.15+deb14-sh7751r"},
          {"reference": "linux-base-7.2.15+deb14-sparc64"},
          {"reference": "linux-base-7.2.15+deb14-test"},
          {"reference": "linux-base-alpha-generic"},
          {"reference": "linux-base-armmp"},
          {"reference": "linux-base-armmp-lpae"},
          {"reference": "linux-base-loong64"}
        ]
      }
    ]
  },
  "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');
}