Debian dla-4251 : libxml2 - 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-4251. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(242881);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/21");

  script_cve_id(
    "CVE-2024-34459",
    "CVE-2025-6021",
    "CVE-2025-6170",
    "CVE-2025-49794",
    "CVE-2025-49796"
  );
  script_xref(name:"IAVA", value:"2024-A-0067-S");
  script_xref(name:"IAVA", value:"2025-A-0707-S");

  script_name(english:"Debian dla-4251 : libxml2 - 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 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the
dla-4251 advisory.

    -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4251-1                [email protected]
    https://www.debian.org/lts/security/                       Guilhem Moulin
    July 26, 2025                                 https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : libxml2
    Version        : 2.9.10+dfsg-6.7+deb11u8
    CVE ID         : CVE-2024-34459 CVE-2025-6021 CVE-2025-6170 CVE-2025-49794
                     CVE-2025-49796
    Debian Bug     : 1071162 1107720 1107755 1107938

    Multiple security issues were found in libxml2, the GNOME XML library,
    which could yield to denial of service or potentially arbitrary code
    execution.

    CVE-2024-34459

        Zhineng Zhong discovered that formatting error messages with `xmllint
        --htmlout` could result in a buffer over-read.

    CVE-2025-6021

        Ahmed Lekssays discovered an integer overflow issue in
        `xmlBuildQName()` which could result in memory corruption or a
        denial of service when processing crafted input.

    CVE-2025-6170

        Ahmed Lekssays discovered a stack-based buffer overflow issue in the
        command-parsing logic of the interactive shell in xmllint.

    CVE-2025-49794

        Nikita Sveshnikov discovered a heap use-after-free issue in the
        schematron.  When processing XPath expressions in Schematron schema
        elements `<sch:name path=/>`, a pointer to freed memory is
        returned and then accessed, leading to undefined behavior or
        potential crashes.

    CVE-2025-49796

        Nikita Sveshnikov discovered a type confusion issue in the
        schematron.  Processing `sch:name` elements and accessing namespace
        information may lead to leading to memory corruption or undefined
        behavior.

    For Debian 11 bullseye, these problems have been fixed in version
    2.9.10+dfsg-6.7+deb11u8.

    We recommend that you upgrade your libxml2 packages.

    For the detailed security status of libxml2 please refer to
    its security tracker page at:
    https://security-tracker.debian.org/tracker/libxml2

    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
    Attachment:
    signature.asc
    Description: PGP signature

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/libxml2");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2024-34459");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-49794");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-49796");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-6021");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-6170");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bullseye/libxml2");
  script_set_attribute(attribute:"solution", value:
"Upgrade the libxml2 packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:N/C:N/I:N/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:R/S:U/C:N/I:N/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-2025-6170");

  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:"2023/12/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/07/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/07/27");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libxml2-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libxml2-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libxml2-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:python3-libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:python3-libxml2-dbg");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"II");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Debian Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2025-2026 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:"^(11)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 11.0', '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': '11.0', 'prefix': 'libxml2', 'reference': '2.9.10+dfsg-6.7+deb11u8'},
    {'release': '11.0', 'prefix': 'libxml2-dev', 'reference': '2.9.10+dfsg-6.7+deb11u8'},
    {'release': '11.0', 'prefix': 'libxml2-doc', 'reference': '2.9.10+dfsg-6.7+deb11u8'},
    {'release': '11.0', 'prefix': 'libxml2-utils', 'reference': '2.9.10+dfsg-6.7+deb11u8'},
    {'release': '11.0', 'prefix': 'python3-libxml2', 'reference': '2.9.10+dfsg-6.7+deb11u8'},
    {'release': '11.0', 'prefix': 'python3-libxml2-dbg', 'reference': '2.9.10+dfsg-6.7+deb11u8'}
];

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_NOTE,
    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, 'libxml2 / libxml2-dev / libxml2-doc / libxml2-utils / python3-libxml2 / etc');
}