Debian dsa-6581 : libunbound-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 dsa-6581. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(371252);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/23");

  script_cve_id(
    "CVE-2026-35501",
    "CVE-2026-50106",
    "CVE-2026-96405",
    "CVE-2026-97206",
    "CVE-2026-109125"
  );
  script_xref(name:"IAVA", value:"2026-A-1194");

  script_name(english:"Debian dsa-6581 : libunbound-dev - 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-6581 advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-6581-1                   [email protected]
    https://www.debian.org/security/                        Yves-Alexis Perez
    October 23, 2026                      https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : unbound
    CVE ID         : CVE-2026-35501 CVE-2026-50106 CVE-2026-96405 CVE-2026-97206
                     CVE-2026-109125

    Multiple security vulnerabilities were discovered in Unbound, a validating,
    recursive, caching DNS resolver.

    CVE-2026-35501

        (DNSSEC) Bypass of a configured island trust anchor underneath an insecure
        parent from an attacker-controlled NSEC record.

    CVE-2026-50106

        (DNSSEC) Possible insecure NXDOMAIN for non-existing records under a
        configured island trust anchor underneath an insecure parent.

    CVE-2026-96405

        Aggregate DNS name chained pointer decompression work leads to degradation
        of service.

    CVE-2026-97206

        DNS-over-QUIC path-migration can lead to use-after-free on multi-threaded
        deployments, leading to potential denial of service.

    CVE-2026-109125

        Possible cache poisoning vulnerability via a cache side-channel exposed by
        'unwanted-reply-threshold'.

    For the stable distribution (trixie), these problems have been fixed in
    version 1.26.2-0+deb13u1.

    We recommend that you upgrade your unbound packages.

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

    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/unbound");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-109125");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-35501");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-50106");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-96405");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-97206");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/trixie/unbound");
  script_set_attribute(attribute:"solution", value:
"Upgrade the libunbound-dev packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/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-2026-50106");

  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:"2026/10/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/23");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libunbound-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libunbound8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:python3-unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:unbound-anchor");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:unbound-host");
  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': 'libunbound-dev', 'reference': '1.26.2-0+deb13u1'},
    {'release': '13.0', 'prefix': 'libunbound8', 'reference': '1.26.2-0+deb13u1'},
    {'release': '13.0', 'prefix': 'python3-unbound', 'reference': '1.26.2-0+deb13u1'},
    {'release': '13.0', 'prefix': 'unbound', 'reference': '1.26.2-0+deb13u1'},
    {'release': '13.0', 'prefix': 'unbound-anchor', 'reference': '1.26.2-0+deb13u1'},
    {'release': '13.0', 'prefix': 'unbound-host', 'reference': '1.26.2-0+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, 'libunbound-dev / libunbound8 / python3-unbound / unbound / etc');
}