Debian dla-4849 : 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-4849. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(370475);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/22");

  script_cve_id(
    "CVE-2025-59375",
    "CVE-2026-56132",
    "CVE-2026-77214",
    "CVE-2026-102633"
  );
  script_xref(name:"IAVA", value:"2026-A-0650-S");
  script_xref(name:"IAVA", value:"2026-A-1100");

  script_name(english:"Debian dla-4849 : 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-4849 advisory.

    - -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4849-1                [email protected]
    https://www.debian.org/lts/security/                       Andrej Shadura
    October 22, 2026                              https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : expat
    Version        : 2.5.0-1+deb12u5
    CVE ID         : CVE-2025-59375 CVE-2026-56132 CVE-2026-77214 CVE-2026-102633

    Multiple vulnerabilities have been found in expat.

    CVE-2025-59375

        The patchset previously uploaded in DLA-4807-1 did not fully address
        the issue since a major part of it was conditionally included only
        when XML_GE was enabled.  This upload enables that define.

    CVE-2026-56132

        A heap-based buffer overflow in doProlog in xmlparse.c caused by
        scaffold backing array reallocation which was mishandled when there
        was data-structure sharing across parsers.

    CVE-2026-77214

        A heap buffer over-read vulnerability in XML_ParseBuffer allowed
        recovering heap pointers, libc function pointers, and code pointers
        sufficient to defeat ASLR and build further exploitation primitives.

    CVE-2026-102633

        An integer overflow vulnerability in expat_realloc() function on
        32-bit platforms when computing allocation sizes was found in the
        code fixing CVE-2025-59375

    For Debian 12 bookworm, these problems have been fixed in version
    2.5.0-1+deb12u5.

    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-2025-59375");
  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-2026-56132");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-77214");
  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: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: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:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-102633");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-56132");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-77214");

  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:"2026/06/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/22");

  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_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:"^(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+deb12u5'},
    {'release': '12.0', 'prefix': 'libexpat1', 'reference': '2.5.0-1+deb12u5'},
    {'release': '12.0', 'prefix': 'libexpat1-dev', 'reference': '2.5.0-1+deb12u5'},
    {'release': '12.0', 'prefix': 'libexpat1-udeb', 'reference': '2.5.0-1+deb12u5'}
];

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');
}