TencentOS Server 2: dracut (TSSA-2026:0970)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Tencent Linux Security Advisory TSSA-2026:0970.
##

include('compat.inc');

if (description)
{
  script_id(342680);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/03");

  script_cve_id("CVE-2026-6893", "CVE-2026-15816");

  script_name(english:"TencentOS Server 2: dracut (TSSA-2026:0970)");

  script_set_attribute(attribute:"synopsis", value:
"The remote TencentOS Server 2 host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of Tencent Linux installed on the remote TencentOS Server 2 host is prior to tested version. It is,
therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0970 advisory.

    Package updates are available for TencentOS Server 2 that fix the following vulnerabilities:

    CVE-2026-6893:
    A flaw was found in dracut. A remote attacker on the adjacent network can exploit this vulnerability by
    providing specially crafted DHCP (Dynamic Host Configuration Protocol) options, such as a malicious
    hostname, to a system using dracut's legacy DHCP path. These options are improperly handled and written
    into temporary shell scripts without proper escaping, leading to command injection. This allows the
    attacker to achieve root code execution within the initramfs, potentially compromising the system's boot
    and network behavior.

    CVE-2026-15816:
    A flaw was found in dracut. The die() error-handling function writes its message into a shell script under
    the initramfs emergency-hook directory without properly shell-quoting it. When the message contains data
    derived from the DHCP ROOT_PATH option, an attacker on the adjacent network who controls a rogue DHCP
    server can inject a command-substitution sequence that executes as root the next time dracut sources its
    emergency hook scripts during standard boot-failure handling.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://mirrors.tencent.com/tlinux/errata/tssa-20260970.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-6893");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/03");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:tencent:tencentos_server:2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:tencent:tencentos_server:dracut");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Tencent Local Security Checks");

  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");
  script_require_keys("Host/local_checks_enabled", "Host/etc/os-release", "Host/TencentOS/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'TencentOS' >!< os_product) audit(AUDIT_OS_NOT, 'TencentOS');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'TencentOS');
if (! preg(pattern:"^2([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'TencentOS 2.x', 'TencentOS ' + os_version);

if (!get_kb_item('Host/TencentOS/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'TencentOS', cpu);

var constraints = [
  {
    'release': '2',
    'pkgs': [
      {'reference':'dracut-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-caps-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-config-generic-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-config-rescue-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-debuginfo-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-fips-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-fips-aesni-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-network-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'dracut-tools-047-8.git20180305.tl2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'dracut / dracut-caps / dracut-config-generic / etc');
}