Oracle Linux 9 : ELSA-2026-67283-0: / nginx:1.26 (ELSA-2026-672830)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2026-672830.
##

include('compat.inc');

if (description)
{
  script_id(345985);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/15");

  script_cve_id("CVE-2026-42533");
  script_xref(name:"IAVA", value:"2026-A-0754");

  script_name(english:"Oracle Linux 9 : ELSA-2026-67283-0: / nginx:1.26 (ELSA-2026-672830)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 9 host has packages installed that are affected by a vulnerability as referenced in the
ELSA-2026-672830 advisory.

    - Fixes CVE-2026-42533
    - Fixes CVE-2026-56434 and CVE-2026-60005
    - nginx: code execution and denial of service (CVE-2026-9256)
    - Resolves: RHEL-176218 - nginx:1.26/nginx: NGINX: Arbitrary Code Execution
      Vulnerability (CVE-2026-42945)
    - CVE-2026-32647 nginx:1.26/nginx: NGINX: Denial of Service or Code
      Execution via specially crafted MP4 files
    - CVE-2026-27651 nginx:1.26/nginx: NGINX: Denial of Service via undisclosed
      requests when ngx_mail_auth_http_module is enabled

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

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://linux.oracle.com/errata/ELSA-2026-67283-0.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/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:H/PR:N/UI:N/S:U/C:H/I:H/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:H/AT:N/PR:N/UI:N/VC:H/VI:H/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-2026-42533");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/07/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/15");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-all-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-filesystem");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-mod-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-mod-http-image-filter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-mod-http-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-mod-http-xslt-filter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-mod-mail");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:nginx-mod-stream");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle Linux 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_info.nasl");
  script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  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) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:os_product)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
if (! preg(pattern:"^9([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Oracle Linux 9.x', 'Oracle Linux ' + os_version);

if (!get_kb_item('Host/RedHat/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$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);

var module_ver = get_kb_item('Host/RedHat/appstream/nginx');
if (isnull(module_ver)) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module nginx:1.26');
if ('1.26' >!< module_ver) audit(AUDIT_PACKAGE_NOT_AFFECTED, 'Module nginx:' + module_ver);

var constraints = {
  'nginx:1.26': [
    {
      'release': '9',
      'pkgs': [
        {'reference':'nginx-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-all-modules-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-core-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-filesystem-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-devel-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-http-image-filter-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-http-perl-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-http-xslt-filter-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-mail-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-stream-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-all-modules-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-core-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-filesystem-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-devel-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-http-image-filter-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-http-perl-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-http-xslt-filter-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-mail-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'},
        {'reference':'nginx-mod-stream-1.26.3-9.0.1.module+el9.8.0+91031+6e548d4b.4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'2'}
      ]
    }
  ]
};

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;
var appstreams_found = 0;
var appstream;
var appstream_name;
var appstream_version;
foreach var module (keys(constraints)) {
  appstream = NULL;
  appstream_name = NULL;
  appstream_version = NULL;
  appstream_split = split(module, sep:':', keep:FALSE);
  if (!empty_or_null(appstream_split)) {
    appstream_name = appstream_split[0];
    appstream_version = appstream_split[1];
    if (!empty_or_null(appstream_name)) appstream = get_one_kb_item('Host/RedHat/appstream/' + appstream_name);
  }
  if (!empty_or_null(appstream) && appstream_version == appstream || appstream_name == 'all') {
    appstreams_found++;
    foreach var module_array ( constraints[module] ) {
      # Check that the target release is equal to the affected release
      if (!empty_or_null(module_array['release'])){
        if (module_array['release'] != os_release) continue;
      }
      if (!empty_or_null(module_array['sp'])){
        if (module_array['sp'] != os_sp) continue;
      }
      foreach var package_array ( module_array['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(package_array['reference'])) reference = package_array['reference'];
        if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
        if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
        if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
        if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
        if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
        if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
        if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
        if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
        if (reference &&
            (!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 (!appstreams_found) audit(AUDIT_PACKAGE_NOT_INSTALLED, 'Module nginx:1.26');

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-core / etc');
}