Linux Distros Unpatched Vulnerability : CVE-2026-99254

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

include('compat.inc');

if (description)
{
  script_id(375585);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/03");

  script_cve_id("CVE-2026-99254");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-99254");

  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.

  - io_uring: don't flood a cancelling task with task_work io_ring_exit_work() asks each task which has used
    the ring to remove its tctx node, by task_work, and repeats that until the list is empty.
    io_tctx_exit_cb() doesn't touch the node while the task is in io_uring_cancel_generic(), which removes all
    the nodes at its end. So the work item queues the callback again as soon as it has completed, for nothing.
    That is more than a waste of time. task_work_run() only returns when it finds the list empty. If the rings
    are released from inside the cancellation, because requests of other rings held the last references to
    their files, up to 64 work items keep sending callbacks to the one task which is running them. It never
    finds the list empty, never gets back to the cancellation, the nodes stay, and so it goes on: a task with
    60 pairs of rings which poll each other ran 280000 callbacks in 5 seconds, 20 seconds after exit_group().
    It ends when all the senders happen to be late at the same time. Until then the task keeps a CPU and the
    work items busy. An exiting task can't be killed meanwhile. execve() cancels the requests in the same way,
    so a live task can get stuck there as well, for minutes. If it takes more than five, the work items run
    into the WARN_ON_ONCE(time_after(jiffies, timeout)) of io_ring_exit_work(). No privilege is needed for any
    of this. If the callback has met a task in cancellation, wait a little before it is sent again. Nobody has
    to wake the work item up for that: either the node is gone by then, or it is the turn of the next round.
    (CVE-2026-99254)

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-2026-99254");
  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-2026-99254");

  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:"2026/11/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/11/03");

  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: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-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-7.2.12+deb14-alpha-generic"},
          {"reference": "linux-base-7.2.12+deb14-amd64"},
          {"reference": "linux-base-7.2.12+deb14-arm64"},
          {"reference": "linux-base-7.2.12+deb14-arm64-16k"},
          {"reference": "linux-base-7.2.12+deb14-armmp"},
          {"reference": "linux-base-7.2.12+deb14-armmp-lpae"},
          {"reference": "linux-base-7.2.12+deb14-cloud-amd64"},
          {"reference": "linux-base-7.2.12+deb14-cloud-arm64"},
          {"reference": "linux-base-7.2.12+deb14-loong64"},
          {"reference": "linux-base-7.2.12+deb14-m68k"},
          {"reference": "linux-base-7.2.12+deb14-parisc"},
          {"reference": "linux-base-7.2.12+deb14-parisc64"},
          {"reference": "linux-base-7.2.12+deb14-powerpc"},
          {"reference": "linux-base-7.2.12+deb14-powerpc64"},
          {"reference": "linux-base-7.2.12+deb14-powerpc64-64k"},
          {"reference": "linux-base-7.2.12+deb14-powerpc64le"},
          {"reference": "linux-base-7.2.12+deb14-powerpc64le-64k"},
          {"reference": "linux-base-7.2.12+deb14-riscv64"},
          {"reference": "linux-base-7.2.12+deb14-rt-amd64"},
          {"reference": "linux-base-7.2.12+deb14-rt-arm64"},
          {"reference": "linux-base-7.2.12+deb14-s390x"},
          {"reference": "linux-base-7.2.12+deb14-sh7751r"},
          {"reference": "linux-base-7.2.12+deb14-sparc64"},
          {"reference": "linux-base-7.2.12+deb14-test"},
          {"reference": "linux-base-alpha-generic"},
          {"reference": "linux-base-armmp"},
          {"reference": "linux-base-armmp-lpae"},
          {"reference": "linux-base-loong64"}
        ]
      }
    ]
  }
};

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');
}