Linux Distros Unpatched Vulnerability : CVE-2026-93250

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

include('compat.inc');

if (description)
{
  script_id(349816);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/24");

  script_cve_id("CVE-2026-93250");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-93250");

  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.

  - vxlan: mdb: Fix use-after-free in vxlan_mdb_flush() vxlan_mdb_flush() iterates over the MDB entries using
    hlist_for_each_entry_safe(), which only tolerates the removal of the current entry. Contrary to the
    comment above the loop, the removal of an entry can trigger the removal of another entry. Flushing the
    remotes of a (*, G) entry also removes the (S, G) entries that were created for its source list, once they
    are left without remotes: vxlan_mdb_remotes_flush() -> vxlan_mdb_remote_del() ->
    vxlan_mdb_remote_srcs_del() -> vxlan_mdb_remote_src_del() -> vxlan_mdb_remote_src_fwd_del() ->
    __vxlan_mdb_del() -> vxlan_mdb_entry_put() Such an entry can be located after the (*, G) entry in the
    list, as vxlan_mdb_entry_get() returns an existing entry without moving it to the head of the list. This
    order is obtained by adding the (S, G) entry before the (*, G) entry, the latter with NLM_F_REPLACE, as
    the addition of the source otherwise fails with -EEXIST. The (S, G) entry is then the entry saved by
    hlist_for_each_entry_safe() and it is freed while the (*, G) entry is processed. The next iteration calls
    hlist_del() on it again, writing LIST_POISON1 to LIST_POISON2 [1]. Besides device deletion, the flush is
    also reachable from RTM_DELMDB with NLM_F_BULK. Fix by re-reading the next entry after the remotes were
    flushed. The current entry cannot be removed by this flush, as source lists can only be configured on (*,
    G) entries and the removed entries are (S, G) entries. It is therefore still linked and its next pointer
    reflects the removals. [1] BUG: KASAN: wild-memory-access in vxlan_mdb_entry_put.part.0+0x328/0x588 Write
    of size 8 at addr dead000000000122 by task ip/327 CPU: 3 UID: 1000 PID: 327 Comm: ip Not tainted 7.2.0-rc7
    #2 PREEMPT Call trace: vxlan_mdb_entry_put.part.0+0x328/0x588 vxlan_mdb_flush+0x1d8/0x25c
    vxlan_mdb_fini+0x8c/0x100 vxlan_uninit+0x1c/0x7c unregister_netdevice_many_notify+0x954/0xd4c
    rtnl_dellink+0x210/0x530 rtnetlink_rcv_msg+0x434/0x4d0 netlink_rcv_skb+0xc4/0x204 rtnetlink_rcv+0x18/0x24
    netlink_unicast+0x4b8/0x548 netlink_sendmsg+0x29c/0x560 ____sys_sendmsg+0x390/0x3ec
    ___sys_sendmsg+0x114/0x188 __sys_sendmsg+0xf0/0x178 __arm64_sys_sendmsg+0x48/0x60
    invoke_syscall.constprop.0+0x58/0x180 el0_svc_common.constprop.0+0x74/0x140 do_el0_svc+0x30/0x40
    el0_svc+0x38/0x98 el0t_64_sync_handler+0xa0/0xe4 el0t_64_sync+0x198/0x19c (CVE-2026-93250)

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-2026-93250");
  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-2026-93250");

  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:"2026/09/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/24");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  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-13");

  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-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');
}