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TencentOS Server 4: python-tornado (TSSA-2025:0977)

🗓️ 04 Jan 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com👁 3 Views

TencentOS Server 4 updates Tornado to fix DoS and event-loop flaws (CVE-2025-67726, 67725, 67724).

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Code
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Tencent Linux Security Advisory TSSA-2025:0977.
##

include('compat.inc');

if (description)
{
  script_id(281640);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/30");

  script_cve_id("CVE-2025-67724", "CVE-2025-67725", "CVE-2025-67726");
  script_xref(name:"IAVB", value:"2026-B-0009-S");

  script_name(english:"TencentOS Server 4: python-tornado (TSSA-2025:0977)");

  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-2025:0977 advisory.

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

    CVE-2025-67726:
    Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an
    inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The
    _parseparam function in httputil.py is used to parse specific HTTP header values, such as those in
    multipart/form-data and repeatedly calls string.count() within a nested loop while processing quoted
    semicolons. If an attacker sends a request with a large number of maliciously crafted parameters in a
    Content-Disposition header, the server's CPU usage increases quadratically (O(n)) during parsing. Due to
    Tornado's single event loop architecture, a single malicious request can cause the entire server to become
    unresponsive for an extended period. This issue is fixed in version 6.5.3.

    CVE-2025-67725:
    Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, a
    single maliciously crafted HTTP request can block the server's event loop for an extended period, caused
    by the HTTPHeaders.add method. The function accumulates values using string concatenation when the same
    header name is repeated, causing a Denial of Service (DoS).  Due to Python string immutability, each
    concatenation copies the entire string, resulting in O(n) time complexity. The severity can vary from
    high if max_header_size has been increased from its default, to low if it has its default value of 64KB.
    This issue is fixed in version 6.5.3.

    CVE-2025-67724:
    Tornado is a Python web framework and asynchronous networking library. In versions 6.5.2 and below, the
    supplied reason phrase is used unescaped in HTTP headers (where it could be used for header injection) or
    in HTML in the default error page (where it could be used for XSS) and can be exploited by passing
    untrusted or malicious data into the reason argument. Used by both RequestHandler.set_status and
    tornado.web.HTTPError, the argument is designed to allow applications to pass custom reason phrases (the
    Not Found in HTTP/1.1 404 Not Found) to the HTTP status line (mainly for non-standard status codes).
    This issue is fixed in version 6.5.3.

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-20250977.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-67724");

  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:"2025/12/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/12/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/04");

  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:python-tornado");
  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':'python-tornado-debugsource-6.3.3-8.tl4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python-tornado-debugsource-6.3.3-8.tl4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python-tornado-doc-6.3.3-8.tl4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python-tornado-doc-6.3.3-8.tl4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-tornado-6.3.3-8.tl4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-tornado-6.3.3-8.tl4', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-tornado-debuginfo-6.3.3-8.tl4', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-tornado-debuginfo-6.3.3-8.tl4', '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_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, 'python-tornado-debugsource / python-tornado-doc / python3-tornado / etc');
}

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30 Apr 2026 00:00Current
7High risk
Vulners AI Score7
CVSS 3.16.1 - 7.5
EPSS0.00212
SSVC
3