Linux Distros Unpatched Vulnerability : CVE-2026-99255

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

include('compat.inc');

if (description)
{
  script_id(375597);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/03");

  script_cve_id("CVE-2026-99255");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-99255");

  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/io-wq: don't hide a link from cancellations A task that exits cancels its tracked requests and
    waits until they are gone. io_uring_cancel_generic() looks everywhere a request can be, and goes to sleep
    if it found nothing to cancel. It is woken up each time one of the requests of the task is completed by
    task work or freed. When io-wq is done with a request that has a link, there is a time in which the next
    request of the link can't be found: io_worker_handle_work() io_assign_current_work(worker, NULL)
    io_wq_free_work(work) io_req_find_next() // takes the link off the request io_free_req() // task work for
    the task io_assign_current_work(worker, linked) io_run_task_work() cond_resched() worker->cur_work =
    linked It is not pending, it is not the current work of a worker, and it is not yet on the list that it is
    about to be parked on. If the pass that the exiting task makes because of io_free_req() falls into that
    time, it finds nothing and the task goes to sleep. The worker then runs the link, which IO_WQ_BIT_EXIT
    doesn't prevent for bounded work. If that parks the request nothing is completed or freed, and nobody
    wakes up the task. If it is the process that exits it can't be killed any more either. NOP, IOSQE_ASYNC |
    IOSQE_IO_LINK FUTEX_WAIT, FUTEX2_PRIVATE exit of the thread, or of the process, up to 63us later With four
    of these per round 5 to 8 of 10,000 rounds hang (4 CPUs, KVM): io_uring_cancel_generic do_exit Commit
    f8b632e89a10 (io_uring: tighten task exit cancellations) is about the same gap, and makes the task look
    again for whatever happens before io_free_req(). Free the request once the link is the current work of the
    worker, or pending. Whoever is woken up by that can find the link, until it is parked where cancellations
    look as well. To do so split io_wq_free_work() in two. (CVE-2026-99255)

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-2026-99255");
  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-2026-99255");

  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');
}