Debian dla-4765 : expat - security update

#%NASL_MIN_LEVEL 80900
#
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory dla-4765. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(341830);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/31");

  script_cve_id(
    "CVE-2026-50219",
    "CVE-2026-56131",
    "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-2026-72522",
    "CVE-2026-76957"
  );
  script_xref(name:"IAVA", value:"2026-A-0650-S");
  script_xref(name:"IAVA", value:"2026-A-0899");

  script_name(english:"Debian dla-4765 : expat - security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing one or more security-related updates.");
  script_set_attribute(attribute:"description", value:
"The remote Debian 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the
dla-4765 advisory.

    - -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4765-1                [email protected]
    https://www.debian.org/lts/security/                       Andrej Shadura
    August 31, 2026                               https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : expat
    Version        : 2.5.0-1+deb12u3
    CVE ID         : CVE-2026-50219 CVE-2026-56131 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-2026-72522 CVE-2026-76957

    CVE-2026-50219, CVE-2026-56131, CVE-2026-76957

        Calling certain libexpat functions from within a handler could cause
        use-after-free.

    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

        Integer overflow in several functions.

    CVE-2026-56412

        A missing reentrancy guard around CDATA section handler calls could
        cause use-after-free.

    CVE-2026-72522

        An out-of-bounds read in expat's internal UTF-16 conversion functions
        could cause an infinite loop when processing crafted input, resulting
        in a denial of service.

    For Debian 12 bookworm, these problems have been fixed in version
    2.5.0-1+deb12u3.

    We recommend that you upgrade your expat packages.

    For the detailed security status of expat please refer to
    its security tracker page at:
    https://security-tracker.debian.org/tracker/expat

    Further information about Debian LTS security advisories, how to apply
    these updates to your system and frequently asked questions can be
    found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian 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://security-tracker.debian.org/tracker/source-package/expat");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-50219");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56131");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56403");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56404");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56405");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56406");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56407");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56408");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56409");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56410");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56411");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-56412");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-72522");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-76957");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bookworm/expat");
  script_set_attribute(attribute:"solution", value:
"Upgrade the expat packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-56412");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-56405");

  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:"2026/06/04");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/31");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:expat");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libexpat1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libexpat1-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libexpat1-udeb");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  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:"Debian 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/Debian/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);
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);

var debian_release = get_kb_item('Host/Debian/release');
if ( isnull(debian_release) ) audit(AUDIT_OS_NOT, 'Debian');
debian_release = chomp(debian_release);
if (! preg(pattern:"^(12)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 12.0', 'Debian ' + debian_release);
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) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Debian', cpu);

var pkgs = [
    {'release': '12.0', 'prefix': 'expat', 'reference': '2.5.0-1+deb12u3'},
    {'release': '12.0', 'prefix': 'libexpat1', 'reference': '2.5.0-1+deb12u3'},
    {'release': '12.0', 'prefix': 'libexpat1-dev', 'reference': '2.5.0-1+deb12u3'},
    {'release': '12.0', 'prefix': 'libexpat1-udeb', 'reference': '2.5.0-1+deb12u3'}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var _release = NULL;
  var prefix = NULL;
  var reference = NULL;
  if (!empty_or_null(package_array['release'])) _release = package_array['release'];
  if (!empty_or_null(package_array['prefix'])) prefix = package_array['prefix'];
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (_release && prefix && reference) {
    if (deb_check(release:_release, prefix:prefix, reference:reference)) flag++;
  }
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : deb_report_get()
  );
  exit(0);
}
else
{
  var tested = deb_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'expat / libexpat1 / libexpat1-dev / libexpat1-udeb');
}