Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : Flatpak vulnerabilities (USN-8741-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8741-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(344634);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/10");

  script_cve_id("CVE-2026-34078", "CVE-2026-34079");
  script_xref(name:"IAVA", value:"2026-A-0317");
  script_xref(name:"USN", value:"8741-1");

  script_name(english:"Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS : Flatpak vulnerabilities (USN-8741-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS host has packages installed that are affected by
multiple vulnerabilities as referenced in the USN-8741-1 advisory.

    It was discovered that Flatpak did not properly validate paths in sandbox-expose options. A malicious or
    compromised Flatpak app could use app-controlled symlinks to access arbitrary host files and gain code
    execution in the host context. This issue was addressed in Ubuntu Ubuntu 20.04 LTS, Ubuntu 22.04 LTS and
    Ubuntu 24.04 LTS. (CVE-2026-34078)

    It was discovered that Flatpak did not properly validate paths when

    removing outdated ld.so cache files. A malicious or compromised Flatpak app could use this issue to delete
    arbitrary files on the host.

    (CVE-2026-34079)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/notices/USN-8741-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:L/PR:N/UI:N/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:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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-2026-34078");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/04/07");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:flatpak");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:flatpak-tests");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:gir1.2-flatpak-1.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libflatpak0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Ubuntu Local Security Checks");

  script_copyright(english:"Ubuntu Security Notice (C) 2026 Canonical, Inc. / NASL script (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('18.04' >< os_release || '20.04' >< os_release || '22.04' >< os_release || '24.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04 / 20.04 / 22.04 / 24.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '18.04', 'pkgname': 'flatpak', 'pkgver': '1.0.9-0ubuntu0.4+esm1'},
    {'osver': '18.04', 'pkgname': 'flatpak-tests', 'pkgver': '1.0.9-0ubuntu0.4+esm1'},
    {'osver': '18.04', 'pkgname': 'gir1.2-flatpak-1.0', 'pkgver': '1.0.9-0ubuntu0.4+esm1'},
    {'osver': '18.04', 'pkgname': 'libflatpak0', 'pkgver': '1.0.9-0ubuntu0.4+esm1'},
    {'osver': '20.04', 'pkgname': 'flatpak', 'pkgver': '1.6.5-0ubuntu0.5+esm1'},
    {'osver': '20.04', 'pkgname': 'flatpak-tests', 'pkgver': '1.6.5-0ubuntu0.5+esm1'},
    {'osver': '20.04', 'pkgname': 'gir1.2-flatpak-1.0', 'pkgver': '1.6.5-0ubuntu0.5+esm1'},
    {'osver': '20.04', 'pkgname': 'libflatpak0', 'pkgver': '1.6.5-0ubuntu0.5+esm1'},
    {'osver': '22.04', 'pkgname': 'flatpak', 'pkgver': '1.12.7-1ubuntu0.1+esm1'},
    {'osver': '22.04', 'pkgname': 'flatpak-tests', 'pkgver': '1.12.7-1ubuntu0.1+esm1'},
    {'osver': '22.04', 'pkgname': 'gir1.2-flatpak-1.0', 'pkgver': '1.12.7-1ubuntu0.1+esm1'},
    {'osver': '22.04', 'pkgname': 'libflatpak0', 'pkgver': '1.12.7-1ubuntu0.1+esm1'},
    {'osver': '24.04', 'pkgname': 'flatpak', 'pkgver': '1.14.6-1ubuntu0.1+esm1'},
    {'osver': '24.04', 'pkgname': 'flatpak-tests', 'pkgver': '1.14.6-1ubuntu0.1+esm1'},
    {'osver': '24.04', 'pkgname': 'gir1.2-flatpak-1.0', 'pkgver': '1.14.6-1ubuntu0.1+esm1'},
    {'osver': '24.04', 'pkgname': 'libflatpak0', 'pkgver': '1.14.6-1ubuntu0.1+esm1'}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (osver && pkgname && pkgver) {
    if (deb_check(release:osver, prefix:pkgname, reference:pkgver, cves:cves)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'flatpak / flatpak-tests / gir1.2-flatpak-1.0 / libflatpak0');
}