CentOS Linux 7 [TuxCare] Security Update: flatpak / flatpak-builder / flatpak-devel / flatpak-libs (CENTOS7:CLSA-2026:1777541348)

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

include('compat.inc');

if (description)
{
  script_id(351871);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id("CVE-2021-43860");
  script_xref(name:"CLSA", value:"2026:1777541348");

  script_name(english:"CentOS Linux 7 [TuxCare] Security Update: flatpak / flatpak-builder / flatpak-devel / flatpak-libs (CENTOS7:CLSA-2026:1777541348)");

  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 7 host has packages installed that are affected by a vulnerability as referenced in the TuxCare
CENTOS7:CLSA-2026:1777541348 advisory.

  - Flatpak is a Linux application sandboxing and distribution framework. Prior to versions 1.12.3 and 1.10.6,
    Flatpak doesn't properly validate that the permissions displayed to the user for an app at install time
    match the actual permissions granted to the app at runtime, in the case that there's a null byte in the
    metadata file of an app. Therefore apps can grant themselves permissions without the consent of the user.
    Flatpak shows permissions to the user during install by reading them from the xa.metadata key in the
    commit metadata. This cannot contain a null terminator, because it is an untrusted GVariant. Flatpak
    compares these permissions to the *actual* metadata, from the metadata file to ensure it wasn't lied to.
    However, the actual metadata contents are loaded in several places where they are read as simple C-style
    strings. That means that, if the metadata file includes a null terminator, only the content of the file
    from *before* the terminator gets compared to xa.metadata. Thus, any permissions that appear in the
    metadata file after a null terminator are applied at runtime but not shown to the user. So maliciously
    crafted apps can give themselves hidden permissions. Users who have Flatpaks installed from untrusted
    sources are at risk in case the Flatpak has a maliciously crafted metadata file, either initially or in an
    update. This issue is patched in versions 1.12.3 and 1.10.6. As a workaround, users can manually check the
    permissions of installed apps by checking the metadata file or the xa.metadata key on the commit metadata.
    (CVE-2021-43860)

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/centos7els/advisories/2026/clsa-2026_1777541348.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?de7af726");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1777541348");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS7:CLSA-2026:1777541348.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/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-2021-43860");

  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:"2022/01/12");
  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:"^7([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 7', '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': '7',
    'pkgs': [
      {'reference':'flatpak-1.0.9-13.el7_9.tuxcare.els2', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-builder-1.0.0-13.el7_9.tuxcare.els2', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-devel-1.0.9-13.el7_9.tuxcare.els2', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'flatpak-libs-1.0.9-13.el7_9.tuxcare.els2', 'cpu':'x86_64', 'el_string':'el7_9', '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, 'flatpak / flatpak-builder / flatpak-devel / flatpak-libs');
}