Debian dla-4690 : liblzma-dev - 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-4690. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(328854);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/22");

  script_cve_id("CVE-2026-34743");

  script_name(english:"Debian dla-4690 : liblzma-dev - 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 11 host has packages installed that are affected by a vulnerability as referenced in the dla-4690
advisory.

    - -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4690-1                [email protected]
    https://www.debian.org/lts/security/                           Chris Lamb
    July 20, 2026                                 https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : xz-utils
    Version        : 5.2.5-2.1~deb11u2
    CVE ID         : CVE-2026-34743
    Debian Bug     : 1132497

    It was discovered that there was a potential buffer overflow in
    xz-utils, a popular data-compression utility and library.

    CVE-2026-34743

        If the lzma_index_decoder function was used to decode an index
        that contained no records, the resulting lzma_index was left in a
        state where where a subsequent lzma_index_append would allocate
        too little memory and a buffer overflow would therefore occur.

    For Debian 11 bullseye, this problem has been fixed in version
    5.2.5-2.1~deb11u2;

    We recommend that you upgrade your xz-utils packages.

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

    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 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/xz-utils");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-34743");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bullseye/xz-utils");
  script_set_attribute(attribute:"solution", value:
"Upgrade the liblzma-dev packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/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:N/AC:L/PR:N/UI:N/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:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/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-2026-34743");

  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:"2026/04/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:liblzma-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:liblzma-doc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:liblzma5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:xz-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:xzdec");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  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:"^(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': 'liblzma-dev', 'reference': '5.2.5-2.1~deb11u2'},
    {'release': '11.0', 'prefix': 'liblzma-doc', 'reference': '5.2.5-2.1~deb11u2'},
    {'release': '11.0', 'prefix': 'liblzma5', 'reference': '5.2.5-2.1~deb11u2'},
    {'release': '11.0', 'prefix': 'xz-utils', 'reference': '5.2.5-2.1~deb11u2'},
    {'release': '11.0', 'prefix': 'xzdec', 'reference': '5.2.5-2.1~deb11u2'}
];

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, 'liblzma-dev / liblzma-doc / liblzma5 / xz-utils / xzdec');
}