Debian dsa-6566 : 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-6566. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(366409);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/16");

  script_cve_id(
    "CVE-2026-66046",
    "CVE-2026-76956",
    "CVE-2026-76957",
    "CVE-2026-77214",
    "CVE-2026-93990",
    "CVE-2026-102633"
  );
  script_xref(name:"IAVA", value:"2026-A-0925-S");
  script_xref(name:"IAVA", value:"2026-A-1045");
  script_xref(name:"IAVA", value:"2026-A-1100");

  script_name(english:"Debian dsa-6566 : 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 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the
dsa-6566 advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-6566-1                   [email protected]
    https://www.debian.org/security/                     Salvatore Bonaccorso
    October 16, 2026                      https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : expat
    CVE ID         : CVE-2026-66046 CVE-2026-76956 CVE-2026-76957 CVE-2026-77214
                     CVE-2026-93990 CVE-2026-102633
    Debian Bug     : 1144925 1144926 1144927 1148665 1149507 1150320

    Several vulnerabilities have been discovered in Expat, an XML parsing C
    library, which could result in denial of service or potentially the
    execution of arbitrary code, if a malformed XML file is processed.

    For the stable distribution (trixie), these problems have been fixed in
    version 2.9.0-1~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 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-2026-102633");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-66046");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-76956");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-76957");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-77214");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-93990");
  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: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:H/VA:N/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-2026-93990");

  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:"2026/08/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/16");

  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_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_info2.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': '2.9.0-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libexpat1', 'reference': '2.9.0-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libexpat1-dev', 'reference': '2.9.0-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libexpat1-udeb', 'reference': '2.9.0-1~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');
}