AlmaLinux 9.2 [TuxCare] Security Update: python3.11-urllib3 Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1770035896)

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

include('compat.inc');

if (description)
{
  script_id(351661);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2025-66418", "CVE-2025-66471", "CVE-2026-21441");
  script_xref(name:"CLSA", value:"2026:1770035896");

  script_name(english:"AlmaLinux 9.2 [TuxCare] Security Update: python3.11-urllib3 Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1770035896)");

  script_set_attribute(attribute:"synopsis", value:
"The AlmaLinux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The AlmaLinux 9.2 host has a package installed that is affected by multiple vulnerabilities as referenced in the TuxCare
ALMALINUX9.2:CLSA-2026:1770035896 advisory.

  - urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.24 and prior to 2.6.0,
    the number of links in the decompression chain was unbounded allowing a malicious server to insert a
    virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation
    for the decompressed data. This vulnerability is fixed in 2.6.0. (CVE-2025-66418)

  - urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.0 and prior to 2.6.0, the
    Streaming API improperly handles highly compressed data. urllib3's streaming API is designed for the
    efficient handling of large HTTP responses by reading the content in chunks, rather than loading the
    entire response body into memory at once. When streaming a compressed response, urllib3 can perform
    decoding or decompression based on the HTTP Content-Encoding header (e.g., gzip, deflate, br, or zstd).
    The library must read compressed data from the network and decompress it until the requested chunk size is
    met. Any resulting decompressed data that exceeds the requested amount is held in an internal buffer for
    the next read operation. The decompression logic could cause urllib3 to fully decode a small amount of
    highly compressed data in a single operation. This can result in excessive resource consumption (high CPU
    usage and massive memory allocation for the decompressed data. (CVE-2025-66471)

  - urllib3 is an HTTP client library for Python. urllib3's streaming API is designed for the efficient
    handling of large HTTP responses by reading the content in chunks, rather than loading the entire response
    body into memory at once. urllib3 can perform decoding or decompression based on the HTTP `Content-
    Encoding` header (e.g., `gzip`, `deflate`, `br`, or `zstd`). When using the streaming API, the library
    decompresses only the necessary bytes, enabling partial content consumption. Starting in version 1.22 and
    prior to version 2.6.3, for HTTP redirect responses, the library would read the entire response body to
    drain the connection and decompress the content unnecessarily. This decompression occurred even before any
    read methods were called, and configured read limits did not restrict the amount of decompressed data. As
    a result, there was no safeguard against decompression bombs. A malicious server could exploit this to
    trigger excessive resource consumption on the client. Applications and libraries are affected when they
    stream content from untrusted sources by setting `preload_content=False` when they do not disable
    redirects. Users should upgrade to at least urllib3 v2.6.3, in which the library does not decode content
    of redirect responses when `preload_content=False`. If upgrading is not immediately possible, disable
    redirects by setting `redirect=False` for requests to untrusted source. (CVE-2026-21441)

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/almalinux9.2esu/advisories/2026/clsa-2026_1770035896.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4686c91d");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1770035896");
  script_set_attribute(attribute:"solution", value:
"Update the affected python3.11-urllib3 package based on the guidance in TuxCare advisory
ALMALINUX9.2:CLSA-2026:1770035896.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  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:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-21441");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_severity", value:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2025/12/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/02/02");
  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:"Alma 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_info2.nasl");
  script_require_keys("Host/OS/extended-third-party", "Host/local_checks_enabled", "Host/AlmaLinux/release", "Host/AlmaLinux/rpm-list", "Host/cpu");

  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) || 'AlmaLinux' >!< os_product) audit(AUDIT_OS_NOT, 'AlmaLinux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'AlmaLinux');
if (! preg(pattern:"^9.2([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'AlmaLinux 9.2', 'AlmaLinux ' + os_version);

if (!get_kb_item('Host/AlmaLinux/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, 'AlmaLinux', cpu);


var constraints = [
  {
    'release': '9',
    'sp': '2',
    'pkgs': [
      {'reference':'python3.11-urllib3-1.26.12-5.el9.tuxcare.els2', 'sp':'2', '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, 'python3.11-urllib3');
}