CentOS Linux 7 [TuxCare] Security Update: nginx / nginx-all-modules / nginx-filesystem / nginx-mod-devel / etc Multiple Vulnerabilities (CENTOS7:CLSA-2026:1790172301)

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

include('compat.inc');

if (description)
{
  script_id(353301);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2026-27651", "CVE-2026-27654", "CVE-2026-27784");
  script_xref(name:"CLSA", value:"2026:1790172301");

  script_name(english:"CentOS Linux 7 [TuxCare] Security Update: nginx / nginx-all-modules / nginx-filesystem / nginx-mod-devel / etc Multiple Vulnerabilities (CENTOS7:CLSA-2026:1790172301)");

  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 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the
TuxCare CENTOS7:CLSA-2026:1790172301 advisory.

  - When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed
    requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP
    authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait
    response header. Note: Software versions which have reached End of Technical Support (EoTS) are not
    evaluated. (CVE-2026-27651)

  - 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)

  - The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module,
    which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination,
    using a specially crafted MP4 file. The issue only affects 32-bit NGINX Open Source if it is built with
    the ngx_http_mp4_module module and the mp4 directive is used in the configuration file. Additionally, the
    attack is possible only if an attacker can trigger the processing of a specially crafted MP4 file with the
    ngx_http_mp4_module module. Note: Software versions which have reached End of Technical Support (EoTS) are
    not evaluated. (CVE-2026-27784)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos7els/advisories/2026/clsa-2026_1790172301.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c4fb1995");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1790172301");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS7:CLSA-2026:1790172301.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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-2026-27784");
  script_set_attribute(attribute:"cvss4_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:"2026/09/23");
  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:"^7([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 7', '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': '7',
    'pkgs': [
      {'reference':'nginx-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-all-modules-1.20.1-10.el7.tuxcare.els9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-filesystem-1.20.1-10.el7.tuxcare.els9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-devel-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-image-filter-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-perl-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-http-xslt-filter-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-mail-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'nginx-mod-stream-1.20.1-10.el7.tuxcare.els9', 'cpu':'x86_64', '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_WARNING,
      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 / nginx-mod-devel / etc');
}