EulerOS Virtualization 2.11.1 : libssh (EulerOS-SA-2026-3433)

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

include('compat.inc');

if (description)
{
  script_id(348011);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/18");

  script_cve_id(
    "CVE-2025-4877",
    "CVE-2025-4878",
    "CVE-2025-5318",
    "CVE-2025-5372",
    "CVE-2025-8114",
    "CVE-2025-8277",
    "CVE-2026-0964",
    "CVE-2026-0965",
    "CVE-2026-0966",
    "CVE-2026-0967",
    "CVE-2026-0968",
    "CVE-2026-3731"
  );
  script_xref(name:"IAVA", value:"2025-A-0462-S");
  script_xref(name:"IAVA", value:"2025-A-0692-S");
  script_xref(name:"IAVA", value:"2026-A-0166-S");

  script_name(english:"EulerOS Virtualization 2.11.1 : libssh (EulerOS-SA-2026-3433)");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS Virtualization host is missing multiple security updates.");
  script_set_attribute(attribute:"description", value:
"According to the versions of the libssh package installed, the EulerOS Virtualization installation on the remote host is
affected by the following vulnerabilities :

    A flaw was found in libssh versions built with OpenSSL versions older than 3.0, specifically in the
    ssh_kdf() function responsible for key derivation. Due to inconsistent interpretation of return values
    where OpenSSL uses 0 to indicate failure and libssh uses 0 for successthe function may mistakenly
    return a success status even when key derivation fails. This results in uninitialized cryptographic key
    buffers being used in subsequent communication, potentially compromising SSH sessions' confidentiality,
    integrity, and availability.(CVE-2025-5372)

    A flaw was found in the libssh library. An out-of-bounds read can be triggered in the sftp_handle function
    due to an incorrect comparison check that permits the function to access memory beyond the valid handle
    list and to return an invalid pointer, which is used in further processing. This vulnerability allows an
    authenticated remote attacker to potentially read unintended memory regions, exposing sensitive
    information or affect service behavior.(CVE-2025-5318)

    There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large
    input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can
    experience an integer overflow leading to a memory under allocation, when that happens it's possible that
    the program perform out of bounds write leading to a heap corruption.This issue affects only 32-bits
    builds of libssh.(CVE-2025-4877)

    A vulnerability was found in libssh, where an uninitialized variable exists under certain conditions in
    the privatekey_from_file() function. This flaw can be triggered if the file specified by the filename
    doesn't exist and may lead to possible signing failures or heap corruption.(CVE-2025-4878)

    A flaw was found in libssh, a library that implements the SSH protocol. When calculating the session ID
    during the key exchange (KEX) process, an allocation failure in cryptographic functions may lead to a NULL
    pointer dereference. This issue can cause the client or server to crash.(CVE-2025-8114)

    A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends
    incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually
    exhaust system memory. This issue can lead to crashes on the client side, particularly when using
    libgcrypt, which impacts application stability and availability.(CVE-2025-8277)

    The API function `ssh_get_hexa()` is vulnerable, when 0-lenght input is provided to this function. This
    function is used internally in `ssh_get_fingerprint_hash()` and `ssh_print_hexa()` (deprecated),which is
    vulnerable to the same input (length is provided by the calling application).The function is also used
    internally in the gssapi code for logging the OIDs received by the server during GSSAPI authentication.
    This could be triggered remotely, when the server allows GSSAPI authentication and logging verbosity is
    set at least to SSH_LOG_PACKET (3). This could cause self-DoS of the per-connection daemon
    process.(CVE-2026-0966)

    A flaw was found in libssh in which a malicious SFTP (SSH File Transfer Protocol) server can exploit this
    by sending a malformed 'longname' field within an `SSH_FXP_NAME` message during a file listing operation.
    This missing null check can lead to reading beyond allocated memory on the heap. This can cause unexpected
    behavior or lead to a denial of service (DoS) due to application crashes.(CVE-2026-0968)

    A flaw was found in libssh where it can attempt to open arbitrary files during configuration parsing. A
    local attacker can exploit this by providing a malicious configuration file or when the system is
    misconfigured. This vulnerability could lead to a Denial of Service (DoS) by causing the system to try and
    access dangerous files, such as block devices or large system files, which can disrupt normal
    operations.(CVE-2026-0965)

    A malicious SCP server can send unexpected paths that could make the client application override local
    files outside of working directory.This could be misused to create malicious executable or configuration
    files and make the user execute them under specific consequences.This is the same issue as in OpenSSH,
    tracked as CVE-2019-6111.(CVE-2026-0964)

    A flaw was found in libssh. A remote attacker, by controlling client configuration files or known_hosts
    files, could craft specific hostnames that when processed by the `match_pattern()` function can lead to
    inefficient regular expression backtracking. This can cause timeouts and resource exhaustion, resulting in
    a Denial of Service (DoS) for the client.(CVE-2026-0967)

    A weakness has been identified in libssh up to 0.11.3. The impacted element is the function
    sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension
    Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may
    be performed from remote. Upgrading to version 0.11.4 and 0.12.0 is sufficient to resolve this issue. This
    patch is called 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60. You should upgrade the affected
    component.(CVE-2026-3731)

Tenable has extracted the preceding description block directly from the EulerOS Virtualization libssh security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://developer.huaweicloud.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2026-3433
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f4ac539b");
  script_set_attribute(attribute:"solution", value:
"Update the affected libssh packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  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:L/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:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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-2026-3731");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2025-5372");

  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:"2025/02/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/18");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libssh");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:uvp:2.11.1");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Huawei 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_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/uvp_version");

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var _release = get_kb_item("Host/EulerOS/release");
if (isnull(_release) || _release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
var uvp = get_kb_item("Host/EulerOS/uvp_version");
if (uvp != "2.11.1") audit(AUDIT_OS_NOT, "EulerOS Virtualization 2.11.1");
if (!get_kb_item("Host/EulerOS/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 && cpu !~ "^i[3-6]86$" && "aarch64" >!< cpu && "x86" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("aarch64" >!< cpu) audit(AUDIT_ARCH_NOT, "aarch64", cpu);

var flag = 0;

var pkgs = [
  "libssh-0.9.6-2.h20.eulerosv2r11"
];

foreach (var pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", reference:pkg)) 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, "libssh");
}