Ubuntu 14.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / Pro Realtime 22.04 LTS : libssh2 vulnerabilities (USN-8799-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8799-1. 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(349108);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/23");

  script_cve_id(
    "CVE-2026-58050",
    "CVE-2026-58051",
    "CVE-2026-66032",
    "CVE-2026-66034"
  );
  script_xref(name:"USN", value:"8799-1");

  script_name(english:"Ubuntu 14.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / Pro Realtime 22.04 LTS : libssh2 vulnerabilities (USN-8799-1)");

  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 14.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / Pro Realtime 22.04 LTS host has a package installed
that is affected by multiple vulnerabilities as referenced in the USN-8799-1 advisory.

    It was discovered that libssh2 incorrectly handled certain publickey subsystem attributes. A remote
    attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly
    execute arbitrary code. (CVE-2026-58050)

    It was discovered that libssh2 did not properly initialize publickey list entries before parsing. A remote
    attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly
    execute arbitrary code. (CVE-2026-58051)

    It was discovered that libssh2 incorrectly handled certain SFTP server responses. A remote attacker
    controlling an SSH server could use this issue to cause libssh2 to crash or possibly execute arbitrary
    code. (CVE-2026-66032)

    It was discovered that libssh2 did not properly check bounds in certain

    publickey subsystem responses. A remote attacker controlling a malicious

    SSH server could use this issue to cause a denial of service or possibly

    execute arbitrary code.. (CVE-2026-66034)

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-8799-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected libssh2-1 package.");
  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:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-58050");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-66032");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/22");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  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:Pro:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libssh2-1");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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 (! ('14.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release || '22.04' >< os_release || 'Pro' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 14.04 / 18.04 / 20.04 / 22.04 / Pro', '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': '14.04', 'pkgname': 'libssh2-1', 'pkgver': '1.4.3-2ubuntu0.2+esm4'},
    {'osver': '18.04', 'pkgname': 'libssh2-1', 'pkgver': '1.8.0-1ubuntu0.1+esm1'},
    {'osver': '20.04', 'pkgname': 'libssh2-1', 'pkgver': '1.8.0-2.1ubuntu0.1+esm1'},
    {'osver': '22.04', 'pkgname': 'libssh2-1', 'pkgver': '1.10.0-3ubuntu0.1'},
    {'osver': 'Pro', 'pkgname': 'libssh2-1', 'pkgver': '1.10.0-3ubuntu0.1'}
];

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, 'libssh2-1');
}