CentOS Linux 8 [TuxCare] Security Update: curl / curl-minimal / libcurl / libcurl-devel / libcurl-minimal Multiple Vulnerabilities (CENTOS-STREAM8:CLSA-2026:1774366368)

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

include('compat.inc');

if (description)
{
  script_id(353091);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2026-1965", "CVE-2026-3783", "CVE-2026-3784");
  script_xref(name:"CLSA", value:"2026:1774366368");

  script_name(english:"CentOS Linux 8 [TuxCare] Security Update: curl / curl-minimal / libcurl / libcurl-devel / libcurl-minimal Multiple Vulnerabilities (CENTOS-STREAM8:CLSA-2026:1774366368)");

  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 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the
TuxCare CENTOS-STREAM8:CLSA-2026:1774366368 advisory.

  - libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated
    HTTP or HTTPS request. libcurl features a pool of recent connections so that subsequent requests can reuse
    an existing connection to avoid overhead. When reusing a connection a range of criterion must first be
    met. Due to a logical error in the code, a request that was issued by an application could wrongfully
    reuse an existing connection to the same server that was authenticated using different credentials. One
    underlying reason being that Negotiate sometimes authenticates *connections* and not *requests*, contrary
    to how HTTP is designed to work. An application that allows Negotiate authentication to a server (that
    responds wanting Negotiate) with `user1:password1` and then does another operation to the same server also
    using Negotiate but with `user2:password2` (while the previous connection is still alive) - the second
    request wrongly reused the same connection and since it then sees that the Negotiate negotiation is
    already made, it sends the request over that connection thinking it uses the user2 credentials when it is
    in fact still using the connection authenticated for user1... The set of authentication methods to use is
    set with `CURLOPT_HTTPAUTH`. Applications can disable libcurl's reuse of connections and thus mitigate
    this problem, by using one of the following libcurl options to alter how connections are or are not
    reused: `CURLOPT_FRESH_CONNECT`, `CURLOPT_MAXCONNECTS` and `CURLMOPT_MAX_HOST_CONNECTIONS` (if using the
    curl_multi API). (CVE-2026-1965)

  - When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect to a
    second URL, curl could leak that token to the second hostname under some circumstances. If the hostname
    that the first request is redirected to has information in the used .netrc file, with either of the
    `machine` or `default` keywords, curl would pass on the bearer token set for the first host also to the
    second one. (CVE-2026-3783)

  - curl would wrongly reuse an existing HTTP proxy connection doing CONNECT to a server, even if the new
    request uses different credentials for the HTTP proxy. The proper behavior is to create or use a separate
    connection. (CVE-2026-3784)

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/centos-stream8els/advisories/2026/clsa-2026_1774366368.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dfc52737");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1774366368");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS-STREAM8:CLSA-2026:1774366368.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:C/I:N/A:N");
  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:N/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:"cvss_score_source", value:"CVE-2026-3784");

  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:"Moderate");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/03/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/03/24");
  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:"^8([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 8', '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 (cpu !~ "^i[3-6]86$" && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS Linux', cpu);


var constraints = [
  {
    'release': '8',
    'pkgs': [
      {'reference':'curl-7.61.1-34.el8.tuxcare.els6', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'curl-minimal-7.61.1-34.el8.tuxcare.els6', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libcurl-7.61.1-34.el8.tuxcare.els6', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libcurl-7.61.1-34.el8.tuxcare.els6', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libcurl-devel-7.61.1-34.el8.tuxcare.els6', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libcurl-devel-7.61.1-34.el8.tuxcare.els6', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libcurl-minimal-7.61.1-34.el8.tuxcare.els6', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libcurl-minimal-7.61.1-34.el8.tuxcare.els6', '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, 'curl / curl-minimal / libcurl / libcurl-devel / libcurl-minimal');
}