TencentOS Server 3: libreswan (TSSA-2026:0806)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Tencent Linux Security Advisory TSSA-2026:0806.
##

include('compat.inc');

if (description)
{
  script_id(333148);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/06");

  script_cve_id(
    "CVE-2026-12413",
    "CVE-2026-14957",
    "CVE-2026-50721",
    "CVE-2026-50722"
  );
  script_xref(name:"IAVA", value:"2026-A-0685-S");
  script_xref(name:"IAVA", value:"2026-A-0792");

  script_name(english:"TencentOS Server 3: libreswan (TSSA-2026:0806)");

  script_set_attribute(attribute:"synopsis", value:
"The remote TencentOS Server 3 host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is,
therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0806 advisory.

    Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

    CVE-2026-12413:
    An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued
    exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore
    unknown outer payloads but still store these in a fixed size array msg_digest.digest[PAYLIMIT]. An off-by-
    one error in the assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) causes the daemon to
    abort. No remote code execution is possible. Any configuration that allows IKEv2 connections that do not
    set fragmentation=no are vulnerable. IKEv1 is not affected.

    CVE-2026-14957:
    No description is available for this CVE.

    CVE-2026-50721:
    Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length
    of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA
    Encryption as per RFC 2313. A remote attacker can use a variation on the Bleichenbacher attack to forge
    the SIG payload when small public exponents are being used (e.g., e=3), which could lead to impersonation.
    Additionally, a remote attacker, by encoding a shorter than expected hash in the SIG payload, could
    trigger an assertion leading to denial-of-service. The daemon aborts and restarts; continued exploitation
    causes sustained denial of service. Remote code execution is not possible. X.509 certificate verifications
    of remote IKE peers are not affected.

    CVE-2026-50722:
    Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly verify the
    DER encoding of the ASN.1 digest when the IKEv2 AUTH payload was encoded using RSASSA-PKCS1-v1_5 (RFC
    8017). A remote attacker can use a variation on the Bleichenbacher attack to forge the AUTH payload when
    small public exponents are used (e.g., e=3), leading to impersonation. Additionally, a remote attacker, by
    encoding a shorter than expected hash in the AUTH payload, could trigger an assertion leading to denial-
    of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of service.
    Remote code execution is not possible. X.509 certificate verifications of the remote IKE peer are not
    affected.

Tenable has extracted the preceding description block directly from the Tencent Linux 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://mirrors.tencent.com/tlinux/errata/tssa-20260806.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:N/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:N/I:N/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-2026-50722");

  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:"2026/07/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/06");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:tencent:tencentos_server:3");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:tencent:tencentos_server:libreswan");
  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:"Tencent 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/local_checks_enabled", "Host/etc/os-release", "Host/TencentOS/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');

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) || 'TencentOS' >!< os_product) audit(AUDIT_OS_NOT, 'TencentOS');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'TencentOS');
if (! preg(pattern:"^3([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'TencentOS 3.x', 'TencentOS ' + os_version);

if (!get_kb_item('Host/TencentOS/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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'TencentOS', cpu);

var constraints = [
  {
    'release': '3',
    'pkgs': [
      {'reference':'libreswan-4.12-2.tl3.6', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libreswan-4.12-2.tl3.6', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libreswan-debuginfo-4.12-2.tl3.6', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libreswan-debuginfo-4.12-2.tl3.6', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libreswan-debugsource-4.12-2.tl3.6', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libreswan-debugsource-4.12-2.tl3.6', 'cpu':'x86_64', '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, 'libreswan / libreswan-debuginfo / libreswan-debugsource');
}