CentOS Linux 8.4 [TuxCare] Security Update: python2 / python2-debug / python2-devel / python2-libs / etc (CENTOS8.4:CLSA-2026:1777568294)

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

include('compat.inc');

if (description)
{
  script_id(351788);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2026-6100");
  script_xref(name:"CLSA", value:"2026:1777568294");

  script_name(english:"CentOS Linux 8.4 [TuxCare] Security Update: python2 / python2-debug / python2-devel / python2-libs / etc (CENTOS8.4:CLSA-2026:1777568294)");

  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 8.4 host has packages installed that are affected by a vulnerability as referenced in the TuxCare
CENTOS8.4:CLSA-2026:1777568294 advisory.

  - Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and
    `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-
    used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the
    dangling pointer in this specific error condition. The vulnerability is only present if the program re-
    uses decompressor instances across multiple decompression calls even after a `MemoryError` is raised
    during decompression. Using the helper functions to one-shot decompress data such as `lzma.decompress()`,
    `bz2.decompress()`, `gzip.decompress()`, and `zlib.decompress()` are not affected as a new decompressor
    instance is used per call. If the decompressor instance is not re-used after an error condition, this
    usage is similarly not vulnerable. (CVE-2026-6100)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos8.4els/advisories/2026/clsa-2026_1777568294.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c5a4264a");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1777568294");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS8.4:CLSA-2026:1777568294.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/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:H/PR:N/UI:N/S:U/C:H/I:H/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:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-6100");

  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:"Critical");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/02/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/30");
  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:"^8.4([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 8.4', '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 ('x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS Linux', cpu);


var constraints = [
  {
    'release': '8',
    'sp': '4',
    'pkgs': [
      {'reference':'python2-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python2-debug-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python2-devel-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python2-libs-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python2-test-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python2-tkinter-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python2-tools-2.7.18-4.module_el8.4.0+2389+535225bc.tuxcare.els21', 'sp':'4', 'cpu':'x86_64', 'el_string':'el8.4.0', '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, 'python2 / python2-debug / python2-devel / python2-libs / etc');
}