RHEL 9 : python-pyasn1 (RHSA-2026:4143)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Red Hat Security Advisory RHSA-2026:4143. The text
# itself is copyright (C) Red Hat, Inc.
##

include('compat.inc');

if (description)
{
  script_id(301692);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/03/10");

  script_cve_id("CVE-2026-23490");
  script_xref(name:"RHSA", value:"2026:4143");

  script_name(english:"RHEL 9 : python-pyasn1 (RHSA-2026:4143)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Red Hat host is missing a security update for python-pyasn1.");
  script_set_attribute(attribute:"description", value:
"The remote Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in
the RHSA-2026:4143 advisory.

    Python is an interpreted, interactive, object-oriented programming language, which includes modules,
    classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to
    many system calls and libraries, as well as to various windowing systems.

    Security Fix(es):

    * pyasn1: pyasn1: Denial of Service due to memory exhaustion from malformed RELATIVE-OID (CVE-2026-23490)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and
    other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise 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://access.redhat.com/security/updates/classification/#important");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2430472");
  # https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_4143.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?cc67a41b");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:4143");
  script_set_attribute(attribute:"solution", value:
"Update the RHEL python-pyasn1 package based on the guidance in RHSA-2026:4143.");
  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:"cvss_score_source", value:"CVE-2026-23490");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(770);
  script_set_attribute(attribute:"vendor_severity", value:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/01/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/03/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/03/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:redhat:rhel_eus:9.4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python-pyasn1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python3-pyasn1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:redhat:enterprise_linux:python3-pyasn1-modules");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Red Hat 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", "redhat_repos.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');
include('rhel.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) || 'Red Hat' >!< os_product) audit(AUDIT_OS_NOT, 'Red Hat');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Red Hat');
if (!rhel_check_release(operator: 'eq', os_version: os_version, rhel_version: '9.4')) audit(AUDIT_OS_NOT, 'Red Hat 9.4', 'Red Hat ' + 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$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Red Hat', cpu);

var constraints = [
  {
    'release': '9',
    'sp': '4',
    'repo_relative_urls': [
      'content/aus/rhel9/9.4/x86_64/appstream/debug',
      'content/aus/rhel9/9.4/x86_64/appstream/os',
      'content/aus/rhel9/9.4/x86_64/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/aarch64/appstream/debug',
      'content/e4s/rhel9/9.4/aarch64/appstream/os',
      'content/e4s/rhel9/9.4/aarch64/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/ppc64le/appstream/debug',
      'content/e4s/rhel9/9.4/ppc64le/appstream/os',
      'content/e4s/rhel9/9.4/ppc64le/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/s390x/appstream/debug',
      'content/e4s/rhel9/9.4/s390x/appstream/os',
      'content/e4s/rhel9/9.4/s390x/appstream/source/SRPMS',
      'content/e4s/rhel9/9.4/x86_64/appstream/debug',
      'content/e4s/rhel9/9.4/x86_64/appstream/os',
      'content/e4s/rhel9/9.4/x86_64/appstream/source/SRPMS',
      'content/eus/rhel9/9.4/aarch64/appstream/debug',
      'content/eus/rhel9/9.4/aarch64/appstream/os',
      'content/eus/rhel9/9.4/aarch64/appstream/source/SRPMS',
      'content/eus/rhel9/9.4/ppc64le/appstream/debug',
      'content/eus/rhel9/9.4/ppc64le/appstream/os',
      'content/eus/rhel9/9.4/ppc64le/appstream/source/SRPMS',
      'content/eus/rhel9/9.4/s390x/appstream/debug',
      'content/eus/rhel9/9.4/s390x/appstream/os',
      'content/eus/rhel9/9.4/s390x/appstream/source/SRPMS',
      'content/eus/rhel9/9.4/x86_64/appstream/debug',
      'content/eus/rhel9/9.4/x86_64/appstream/os',
      'content/eus/rhel9/9.4/x86_64/appstream/source/SRPMS'
    ],
    'pkgs': [
      {'reference':'python3-pyasn1-0.4.8-6.el9_4.1', 'sp':'4', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-pyasn1-modules-0.4.8-6.el9_4.1', 'sp':'4', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var applicable_repo_urls = rhel_determine_applicable_repository_urls(constraints:constraints);
if(applicable_repo_urls == RHEL_REPOS_NO_OVERLAP_MESSAGE) exit(0, RHEL_REPO_NOT_ENABLED);

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 repo_relative_urls;
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;
  }

  if (!empty_or_null(constraint['repo_relative_urls'])) repo_relative_urls = constraint['repo_relative_urls'];

  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 &&
        rhel_decide_repo_relative_url_check(required_repo_url_list:repo_relative_urls) &&
        (applicable_repo_urls || (!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)
{
  var subscription_caveat = '\n' +
    'NOTE: This vulnerability check contains fixes that apply to\n' +
    'packages only available in the Red Hat Enterprise Linux\n' +
    'Extended Update Support repository.\n' +
    'Access to this repository requires a paid RHEL subscription.\n';
  var extra = NULL;
  if (isnull(applicable_repo_urls) || !applicable_repo_urls) extra = subscription_caveat + rpm_report_get() + redhat_report_repo_caveat();
  else extra = subscription_caveat + rpm_report_get();
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : extra
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'python3-pyasn1 / python3-pyasn1-modules');
}