TencentOS Server 4: nginx (TSSA-2026:0275)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Tencent Linux Security Advisory TSSA-2026:0275.
##

include('compat.inc');

if (description)
{
  script_id(319729);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/08");

  script_cve_id(
    "CVE-2026-1642",
    "CVE-2026-27651",
    "CVE-2026-27654",
    "CVE-2026-27784",
    "CVE-2026-28753",
    "CVE-2026-28755",
    "CVE-2026-32647"
  );
  script_xref(name:"IAVA", value:"2026-A-0140");
  script_xref(name:"IAVA", value:"2026-A-0280-S");

  script_name(english:"TencentOS Server 4: nginx (TSSA-2026:0275)");

  script_set_attribute(attribute:"synopsis", value:
"The remote TencentOS Server 4 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 4 host is prior to tested version. It is,
therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0275 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    CVE-2026-32647:
    NGINX Open Source and NGINX Plus have a vulnerability in the ngx_http_mp4_module module, which might allow
    an attacker to trigger a buffer over-read or over-write to the NGINX worker memory resulting in its
    termination or possibly code execution, using a specially crafted MP4 file. This issue affects NGINX Open
    Source and NGINX Plus 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-2026-28755:
    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_stream_ssl_module module due to the
    improper handling of revoked certificates when configured with the ssl_verify_client on and ssl_ocsp on
    directives, allowing the TLS handshake to succeed even after an OCSP check identifies the certificate as
    revoked. 


    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

    CVE-2026-28753:
    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_mail_smtp_module module due to the
    improper handling of CRLF sequences in DNS responses. This allows an attacker-controlled DNS server to
    inject arbitrary headers into SMTP upstream requests, leading to potential request manipulation. Note:
    Software versions which have reached End of Technical Support (EoTS) are not evaluated.

    CVE-2026-27784:
    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-2026-27654:
    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-2026-27651:
    When the ngx_mail_auth_http_modulemodule 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-2026-1642:
    A vulnerability exists in NGINX OSS and NGINX Plus when configured to proxy to upstream Transport Layer
    Security (TLS) servers. An attacker with a man-in-the-middle (MITM) position on the upstream server
    sidealong with conditions beyond the attacker's controlmay be able to inject plain text data into
    the response from an upstream proxied server.Note: Software versions which have reached End of
    Technical Support (EoTS) are not evaluated.

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-20260275.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  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:L/UI:N/S:U/C:L/I:L/A:N");
  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:L/AC:L/AT:N/PR:L/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-2026-27654");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-28755");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-27784");

  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:"2026/02/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/08");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:tencent:tencentos_server:4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:tencent:tencentos_server:nginx");
  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:"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:"^4([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'TencentOS 4.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': '4',
    'pkgs': [
      {'reference':'nginx-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-all-modules-1.26.3-1.tl4.ap.2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-core-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-core-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-core-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-core-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-debugsource-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-debugsource-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-filesystem-1.26.3-1.tl4.ap.2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-devel-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-devel-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-image-filter-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-image-filter-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-image-filter-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-image-filter-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-perl-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-perl-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-perl-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-perl-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-xslt-filter-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-xslt-filter-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-xslt-filter-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-http-xslt-filter-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-mail-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-mail-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-mail-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-mail-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-stream-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-stream-1.26.3-1.tl4.ap.2', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-stream-debuginfo-1.26.3-1.tl4.ap.2', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'nginx-mod-stream-debuginfo-1.26.3-1.tl4.ap.2', '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, 'nginx / nginx-all-modules / nginx-core / etc');
}