Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : OpenSSH vulnerabilities (USN-8222-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8222-1. 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(311107);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/02");

  script_cve_id(
    "CVE-2026-35385",
    "CVE-2026-35386",
    "CVE-2026-35387",
    "CVE-2026-35388",
    "CVE-2026-35414"
  );
  script_xref(name:"IAVA", value:"2026-A-0296");
  script_xref(name:"USN", value:"8222-1");

  script_name(english:"Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : OpenSSH vulnerabilities (USN-8222-1)");

  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 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple
vulnerabilities as referenced in the USN-8222-1 advisory.

    Christos Papakonstantinou discovered that the OpenSSH scp tool incorrectly handled the legacy scp protocol
    (-O) option. This could result in certain files being installed setuid or setgid, contrary to
    expectations. (CVE-2026-35385)

    Florian Kohnhuser discovered that OpenSSH incorrectly handled shell metacharacters in usernames within a
    command line. When untrusted usernames and non-default configurations using % in ssh_config are being
    used, an attacker could possibly use this issue to execute arbitrary code. (CVE-2026-35386)

    Christos Papakonstantinou discovered that OpenSSH incorrectly handled parsing the PubkeyAcceptedAlgorithms
    and HostbasedAcceptedAlgorithms options. This could result in unintended ECDSA algorithms being used,
    contrary to expectations. (CVE-2026-35387)

    Michalis Vasileiadis discovered that OpenSSH incorrectly handled proxy-mode multiplexing sessions. This
    could result in no confirmation being asked, contrary to expectations. (CVE-2026-35388)

    Vladimir Tokarev discovered that OpenSSH incorrectly handled certificates with the principal name
    containing a comma character when using user-trusted CA keys in authorized_keys and an authorized_keys
    principals= option that lists more than one principal. This could result in inappropriate principal
    matching, contrary to expectations. (CVE-2026-35414)

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-8222-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  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:"cvss_score_source", value:"CVE-2026-35414");

  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:"2026/04/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:"cpe:/o:canonical:ubuntu_linux:25.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-client-gssapi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-server-gssapi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-sftp-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:openssh-tests");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ssh");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ssh-askpass-gnome");
  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 (! ('22.04' >< os_release || '24.04' >< os_release || '25.10' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 22.04 / 24.04 / 25.10 / 26.04', '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': '22.04', 'pkgname': 'openssh-client', 'pkgver': '1:8.9p1-3ubuntu0.15'},
    {'osver': '22.04', 'pkgname': 'openssh-server', 'pkgver': '1:8.9p1-3ubuntu0.15'},
    {'osver': '22.04', 'pkgname': 'openssh-sftp-server', 'pkgver': '1:8.9p1-3ubuntu0.15'},
    {'osver': '22.04', 'pkgname': 'openssh-tests', 'pkgver': '1:8.9p1-3ubuntu0.15'},
    {'osver': '22.04', 'pkgname': 'ssh', 'pkgver': '1:8.9p1-3ubuntu0.15'},
    {'osver': '22.04', 'pkgname': 'ssh-askpass-gnome', 'pkgver': '1:8.9p1-3ubuntu0.15'},
    {'osver': '24.04', 'pkgname': 'openssh-client', 'pkgver': '1:9.6p1-3ubuntu13.16'},
    {'osver': '24.04', 'pkgname': 'openssh-server', 'pkgver': '1:9.6p1-3ubuntu13.16'},
    {'osver': '24.04', 'pkgname': 'openssh-sftp-server', 'pkgver': '1:9.6p1-3ubuntu13.16'},
    {'osver': '24.04', 'pkgname': 'openssh-tests', 'pkgver': '1:9.6p1-3ubuntu13.16'},
    {'osver': '24.04', 'pkgname': 'ssh', 'pkgver': '1:9.6p1-3ubuntu13.16'},
    {'osver': '24.04', 'pkgname': 'ssh-askpass-gnome', 'pkgver': '1:9.6p1-3ubuntu13.16'},
    {'osver': '25.10', 'pkgname': 'openssh-client', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'openssh-client-gssapi', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'openssh-server', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'openssh-server-gssapi', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'openssh-sftp-server', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'openssh-tests', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'ssh', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '25.10', 'pkgname': 'ssh-askpass-gnome', 'pkgver': '1:10.0p1-5ubuntu5.4'},
    {'osver': '26.04', 'pkgname': 'openssh-client', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'openssh-client-gssapi', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'openssh-server', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'openssh-server-gssapi', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'openssh-sftp-server', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'openssh-tests', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'ssh', 'pkgver': '1:10.2p1-2ubuntu3.2'},
    {'osver': '26.04', 'pkgname': 'ssh-askpass-gnome', 'pkgver': '1:10.2p1-2ubuntu3.2'}
];

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, 'openssh-client / openssh-client-gssapi / openssh-server / etc');
}