Alibaba Cloud Linux 3 : 0207: unbound (ALINUX3-SA-2026:0207)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# Alibaba Cloud Linux Security Advisory ALINUX3-SA-2026:0207.
##

include('compat.inc');

if (description)
{
  script_id(327261);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/16");

  script_cve_id(
    "CVE-2026-40622",
    "CVE-2026-41292",
    "CVE-2026-42534",
    "CVE-2026-44390"
  );

  script_name(english:"Alibaba Cloud Linux 3 : 0207: unbound (ALINUX3-SA-2026:0207)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Alibaba Cloud Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced
in the ALINUX3-SA-2026:0207 advisory.

    Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

    CVE-2026-40622:
    NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain
    names' family of attacks that could extend the ghost domain window by up to one cached TTL configured
    value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be
    able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached
    expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost
    domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-
    referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound
    implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension
    of TTLs for (parent) NS records regardless of their trust.

    CVE-2026-41292:
    NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack
    related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS
    options can hold Unbound threads hostage while they are parsing and creating internal data structures for
    the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1
    contains a patch with a fix to limit acceptable incoming EDNS options (100).

    CVE-2026-42534:
    NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could
    defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age
    of slow running queries and not allow the jostle logic to see them as aged and potential targets for
    replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain
    name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and
    degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit,
    the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to
    resolve are candidates for replacement. The vulnerability then happens because duplicate queries that need
    resolution would skew the aging result by using the timestamp of the latest duplicate query instead of the
    original one that started the resolution effort. Cache and local data response performance remains
    unaffected. Coordinated attacks could raise this to a denial of resolution service. Unbound 1.25.1
    contains a patch with a fix to attach an initial, non-updatable start time for incoming queries that allow
    the jostle logic to work as intended.

    CVE-2026-44390:
    NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability when handling replies with very
    large RRsets that Unbound needs to perform name compression for. Malicious upstream responses with very
    large RRsets with records that don't share a suffix above the root can cause Unbound to spend a
    considerable time applying name compression to downstream replies. This can lead to degraded performance
    and eventually denial of service in well orchestrated attacks. An adversary can exploit the vulnerability
    by querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before
    Unbound replies to the query it will try to apply name compression which was an unbounded operation that
    could lock the CPU until the whole packet was complete. A compression limit was introduced in 1.21.1 for
    this but it didn't account for the case where records would not share any suffix above the root. That
    causes Unbound to go in a different code path because of the compression tree lookup failure and
    eventually not increment the compression counter for those operations. Unbound 1.25.1 contains a patch
    with a fix that increments the compression counter regardless of the compression tree lookup. This is a
    complement fix to CVE-2024-8508.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux 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:"http://mirrors.aliyun.com/alinux/3/cve/alinux3-sa-20260207.xml");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N");
  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:H/A:N");
  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:N/PR:N/UI:N/VC:N/VI:N/VA:H/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-2026-40622");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-41292");

  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:"2026/05/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:unbound-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:unbound-libs");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alibabacloud:alibaba_cloud_linux_3");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Alibaba Cloud Linux 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/Alibaba/release", "Host/Alibaba/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'Alibaba Cloud Linux' >!< os_product) audit(AUDIT_OS_NOT, 'Alibaba Cloud Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Alibaba Cloud Linux');
if (! preg(pattern:"^3([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Alibaba Cloud Linux 3.x', 'Alibaba Cloud Linux ' + os_version);

if (!get_kb_item('Host/Alibaba/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Alibaba Cloud Linux', cpu);

var constraints = [
  {
    'release': '3',
    'pkgs': [
      {'reference':'python3-unbound-1.16.2-9.0.2.al8', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'python3-unbound-1.16.2-9.0.2.al8', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'unbound-1.16.2-9.0.2.al8', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'unbound-1.16.2-9.0.2.al8', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'unbound-devel-1.16.2-9.0.2.al8', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'unbound-devel-1.16.2-9.0.2.al8', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'unbound-libs-1.16.2-9.0.2.al8', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'unbound-libs-1.16.2-9.0.2.al8', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'python3-unbound / unbound / unbound-devel / unbound-libs');
}