EulerOS 2.0 SP13 : expat (EulerOS-SA-2026-4044)

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

include('compat.inc');

if (description)
{
  script_id(364727);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/12");

  script_cve_id(
    "CVE-2026-50219",
    "CVE-2026-56131",
    "CVE-2026-56132",
    "CVE-2026-56403",
    "CVE-2026-56404",
    "CVE-2026-56405",
    "CVE-2026-56406",
    "CVE-2026-56407",
    "CVE-2026-56408",
    "CVE-2026-56409",
    "CVE-2026-56410",
    "CVE-2026-56411",
    "CVE-2026-56412",
    "CVE-2026-66046",
    "CVE-2026-76641",
    "CVE-2026-76957"
  );
  script_xref(name:"IAVA", value:"2026-A-0650-S");
  script_xref(name:"IAVA", value:"2026-A-0925-S");

  script_name(english:"EulerOS 2.0 SP13 : expat (EulerOS-SA-2026-4044)");

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

    libexpat before 2.8.2 has an integer overflow in getAttributeId.(CVE-2026-56405)

    Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory
    corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A
    struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past
    allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a
    wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for
    CVE-2026-66046.(CVE-2026-76641)

    libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_GetBuffer, XML_Parse,
    XML_ParseBuffer, XML_ParserFree, or XML_ParserReset from within handlers in cases of a policy violation.
    Thus, a use-after-free can occur,(CVE-2026-50219)

    xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is
    used.(CVE-2026-56409)

    libexpat before 2.8.2 has an integer overflow in XML_ParseBuffer because it lacked a check that was
    present in XML_Parse.(CVE-2026-56406)

    libexpat before 2.8.2 does not consider XML_TOK_DATA_CHARS in doCdataSection and thus lacks handler call
    depth tracking for various calls from within handlers in cases of a policy violation. Thus, a use-after-
    free can occur. NOTE: this issue exists because of an incomplete fix for CVE-2026-50219.(CVE-2026-56412)

    xmlwf in libexpat before 2.8.2 has an integer overflow in endDoctypeDecl via NOTATION
    declarations.(CVE-2026-56411)

    libexpat before 2.8.2 has an integer overflow in doProlog that is related to storeEntityValue and entity
    textLen.(CVE-2026-56407)

    Expat through 2.8.3 contains a denial of service vulnerability caused by quadratic algorithmic complexity
    in the storeAtts() function in xmlparse.c, where processing N specified attributes with non-normalized
    values triggers an O(N^2) linear scan of elementType-defaultAtts to determine CDATA status. A remote
    unauthenticated attacker can supply a single well-formed XML document of a few megabytes to an application
    parsing untrusted XML to cause excessive CPU consumption, resulting in denial of service without requiring
    authentication, external entity resolution, or non-default parser options.(CVE-2026-66046)

    libexpat before 2.8.2 has an integer overflow in storeAtts.(CVE-2026-56403)

    libexpat before 2.8.2 lacks handler call depth tracking for calls to XML_ResumeParser from within handlers
    in cases of a policy violation. Thus, a use-after-free can occur (similar to the CVE-2026-50219
    situation).(CVE-2026-56131)

    libexpat before 2.8.2 has an integer overflow in addBinding.(CVE-2026-56404)

    libexpat before 2.8.2 has an integer overflow in copyString.(CVE-2026-56408)

    In libexpat before 2.8.2, there is a heap-based buffer overflow in doProlog in xmlparse.c because scaffold
    backing array reallocation is mishandled when there is data-structure sharing across
    parsers.(CVE-2026-56132)

    xmlwf in libexpat before 2.8.2 has an integer overflow in resolveSystemId.(CVE-2026-56410)

    libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-
    free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and
    CVE-2026-56412.(CVE-2026-76957)

Tenable has extracted the preceding description block directly from the EulerOS expat 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-2026-4044
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d98e83ac");
  script_set_attribute(attribute:"solution", value:
"Update the affected expat packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:N/VC:N/VI:N/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-2026-76957");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-76641");

  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:"2026/06/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/12");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:expat");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:expat-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:expat-help");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  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:"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_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("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 (_release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP13");

var sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(13)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP13");

if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP13", "EulerOS UVP " + uvp);

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$" && "aarch64" >!< cpu && "x86" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$" && "x86" >!< cpu) audit(AUDIT_ARCH_NOT, "i686 / x86_64", cpu);

var flag = 0;

var pkgs = [
  "expat-2.4.1-8.h23.eulerosv2r13",
  "expat-devel-2.4.1-8.h23.eulerosv2r13",
  "expat-help-2.4.1-8.h23.eulerosv2r13"
];

foreach (var pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"13", 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, "expat");
}