Debian dsa-6446 : 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 dsa-6446. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(337123);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/18");

  script_cve_id("CVE-2026-72522");

  script_name(english:"Debian dsa-6446 : expat - security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing a security-related update.");
  script_set_attribute(attribute:"description", value:
"The remote Debian 13 host has packages installed that are affected by a vulnerability as referenced in the dsa-6446
advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-6446-1                   [email protected]
    https://www.debian.org/security/                                  Aron Xu
    August 18, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : expat
    CVE ID         : CVE-2026-72522
    Debian Bug     : 1144064

    A flaw was discovered in the UTF-16 decoding support of expat, an XML
    parsing C library, where low surrogates were treated in the same way as
    high surrogates. Parsing crafted XML input may result in an out-of-bounds
    read and a resultant infinite loop, leading to denial of service. Only
    builds with 16 bit character support are affected, which in Debian is the
    libexpatw library shipped in the libexpat1 package.

    In addition, this update corrects a regression introduced in the previous
    security update (DSA-6404-1): on 32 bit architectures, documents larger
    than 2 GiB were incorrectly rejected with an out of memory error.

    For the stable distribution (trixie), this problem has been fixed in
    version 2.8.3-1~deb13u1.

    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 Security Advisories, how to apply
    these updates to your system and frequently asked questions can be
    found at: https://www.debian.org/security/

    Mailing list: [email protected]

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for this issue 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-2026-72522");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/trixie/expat");
  script_set_attribute(attribute:"solution", value:
"Upgrade the expat packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/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:L/AC:L/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-2026-72522");

  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:"2026/08/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/18");

  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:13.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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:"^(13)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 13.0', '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': '13.0', 'prefix': 'expat', 'reference': '2.8.3-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libexpat1', 'reference': '2.8.3-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libexpat1-dev', 'reference': '2.8.3-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libexpat1-udeb', 'reference': '2.8.3-1~deb13u1'}
];

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');
}