CentOS Linux 8.4 [TuxCare] Security Update: nginx / nginx-all-modules / nginx-filesystem / etc (CENTOS8.4:CLSA-2026:1777396606)

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

include('compat.inc');

if (description)
{
  script_id(353007);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2026-27654");
  script_xref(name:"CLSA", value:"2026:1777396606");

  script_name(english:"CentOS Linux 8.4 [TuxCare] Security Update: nginx / nginx-all-modules / nginx-filesystem / etc (CENTOS8.4:CLSA-2026:1777396606)");

  script_set_attribute(attribute:"synopsis", value:
"The CentOS Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The CentOS Linux 8.4 host has packages installed that are affected by a vulnerability as referenced in the TuxCare
CENTOS8.4:CLSA-2026:1777396606 advisory.

  - NGINX Open Source and NGINX Plus have a vulnerability in the ngx_http_dav_module module that might allow
    an attacker to trigger a buffer overflow to the NGINX worker process; this vulnerability may result in
    termination of the NGINX worker process or modification of source or destination file names outside the
    document root. This issue affects NGINX Open Source and NGINX Plus when the configuration file uses DAV
    module MOVE or COPY methods, prefix location (nonregular expression location configuration), and alias
    directives. The integrity impact is constrained because the NGINX worker process user has low privileges
    and does not have access to the entire system. Note: Software versions which have reached End of Technical
    Support (EoTS) are not evaluated. (CVE-2026-27654)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos8.4els/advisories/2026/clsa-2026_1777396606.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4e1b9863");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1777396606");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS8.4:CLSA-2026:1777396606.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-27654");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_severity", value:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/03/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CentOS 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/OS/extended-third-party", "Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list");

  exit(0);
}
include('rpm2.inc');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (empty_or_null(third_party_support) || third_party_support != 'TuxCare') exit(0, 'TuxCare support not enabled.');

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) || 'CentOS Linux' >!< os_product) audit(AUDIT_OS_NOT, 'CentOS Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS Linux');
if (! preg(pattern:"^8.4([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 8.4', 'CentOS Linux ' + os_version);

if (!get_kb_item('Host/CentOS/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) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS Linux', cpu);


var constraints = [
  {
    'release': '8',
    'sp': '4',
    'pkgs': [
      {'reference':'nginx-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-all-modules-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-filesystem-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-image-filter-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-perl-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-xslt-filter-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-mail-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-stream-1.14.1-9.module_el8.4.0+2374+826f574f.tuxcare.els5', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'}
    ]
  }
];

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, 'nginx / nginx-all-modules / nginx-filesystem / etc');
}