EulerOS 2.0 SP15 : unbound (EulerOS-SA-2026-2954)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(332892);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/06");

  script_cve_id(
    "CVE-2026-32792",
    "CVE-2026-33278",
    "CVE-2026-40622",
    "CVE-2026-41292",
    "CVE-2026-42534",
    "CVE-2026-42923",
    "CVE-2026-42944",
    "CVE-2026-42959",
    "CVE-2026-42960",
    "CVE-2026-44390",
    "CVE-2026-44608"
  );

  script_name(english:"EulerOS 2.0 SP15 : unbound (EulerOS-SA-2026-2954)");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS host is missing multiple security updates.");
  script_set_attribute(attribute:"description", value:
"According to the versions of the unbound packages installed, the EulerOS installation on the remote host is affected by
the following vulnerabilities :

    NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a locking inconsistency vulnerability
    that when certain conditions are met (multi-threaded, RPZ XFR reload, RPZ zone with 'rpz-nsip'/'rpz-
    nsdname' triggers) it could result in heap use-after-free and eventual crash. An adversary can exploit the
    vulnerability if conditions are first met on a vulnerable Unbound, i.e., multi-threaded, an RPZ zone with
    'rpz-nsip'/'rpz-nsdname' triggers and an ongoing XFR for that RPZ zone. Local RPZ files do not trigger the
    vulnerability. If the timing is right and an XFR happens at the same time another thread needs to read
    that RPZ zone, the reader may not hold the lock long enough and the thread applying the XFR may free
    objects that the reader is about to walk causing the use-after-free. Unbound 1.25.1 contains a patch with
    a fix to the locking code.(CVE-2026-44608)

    NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where
    the code path to consult the negative cache for DS records does not take into account the limit on NSEC3
    hash calculations introduced in 1.19.1. This leads to degradation of service during the attack. An
    adversary that controls a DNSSEC signed zone can exploit this by signing NSEC3 records with acceptably
    high iterations for child delegations and querying a vulnerable Unbound. Unbound will keep performing the
    allowed hash calculations on the NSEC3 records and will not limit the work by the mitigation introduced in
    1.19.1. As a side effect, a global lock for the negative cache will be held for the duration of the
    hashing, blocking other threads that need to consult the negative cache. Coordinated attacks could raise
    the vulnerability to denial of service. Unbound 1.25.1 contains a patch with a fix to bound the vulnerable
    code path with the existing limit for NSEC3 hash calculations.(CVE-2026-42923)

    NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator
    that enables denial of service and possible remote code execution as a result of deep copying a data
    structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by
    controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend
    validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-
    copies response messages to preserve them across memory region teardown. A struct-assignment bug
    overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the
    resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary
    code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep
    copying the data structure.(CVE-2026-33278)

    NLnet Labs Unbound 1.6.2 up to and including version 1.25.0 has a denial of service vulnerability when
    compiled with DNSCrypt support ('--enable-dnscrypt'). A bad DNSCrypt query could underflow Unbound's
    DNSCrypt packet reading procedure that may lead to heap overflow. A malicious actor can exploit the
    vulnerability with a single bad DNSCrypt query that its decrypted plaintext consists entirely of '0x00'
    bytes and does not contain the expected '0x80' marker. Unbound would then start reading more bytes than
    necessary until it finds a non-'0x00' byte. Based on the underlying memory allocator and the memory
    layout, it could lead to heap overflow while reading followed by a crash. Likelihood of a crash is low,
    since it relies heavily on the underlying memory allocator and the memory layout. If the heap overflow
    does not happen, Unbound's later packet checks will deny the packet. Unbound 1.25.1 contains a patch with
    a fix to bound reading in the given buffer space.(CVE-2026-32792)

    NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap
    overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply
    packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for
    the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by
    attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the
    size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the
    available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data
    and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a
    fix to prevent truncation of the EDNS field size calculation.(CVE-2026-42944)

    NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC
    validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply
    messages for validation, the code uses the wrong counter to calculate write offsets for ADDITIONAL section
    rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease
    the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator
    later dereferences this uninitialized pointer, causing an immediate process crash. An adversary
    controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain
    with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue
    records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write
    offsets.(CVE-2026-42959)

    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-2026-41292)

    NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to poisoning via promiscuous records
    for the authority section. Promiscuous RRSets that complement DNS replies in the authority section can be
    used to trick Unbound to cache such records. If an adversary is able to attach such records in a reply
    (i.e., spoofed packet, fragmentation attack) he would be able to poison Unbound's cache. A malicious actor
    can exploit the possible poisonous effect by injecting RRSets other than NS that are also accompanied by
    address records in a reply, for example MX. This could be achieved by trying to spoof a reply packet or
    fragmentation attacks. Unbound would then accept the relative address records in the additional section
    and cache them if the authority RRSet has enough trust at this point, i.e., in-zone data for the
    delegation point. Unbound 1.25.1 contains a patch with a fix that disregards address records from the
    additional section if they are not explicitly relevant only to authority NS records, mitigating the
    possible poison effect. This is a complement fix to CVE-2025-11411.(CVE-2026-42960)

    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.(CVE-2026-44390)

    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-2026-42534)

    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-2026-40622)

Tenable has extracted the preceding description block directly from the EulerOS unbound security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://developer.huaweicloud.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2026-2954
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?524f176a");
  script_set_attribute(attribute:"solution", value:
"Update the affected unbound packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/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:L/PR:N/UI:N/S:C/C:N/I:H/A:H");
  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:H/VI:H/VA:H/SC:H/SI:H/SA:H");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-33278");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-42960");

  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:"2026/08/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/06");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:python3-unbound");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:unbound-help");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:unbound-libs");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Huawei 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/cpu", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("Host/EulerOS/uvp_version");

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var _release = get_kb_item("Host/EulerOS/release");
if (isnull(_release) || _release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
var uvp = get_kb_item("Host/EulerOS/uvp_version");
if (_release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP15");

var sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(15)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP15");

if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP15", "EulerOS UVP " + uvp);

if (!get_kb_item("Host/EulerOS/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

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 && "x86" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("aarch64" >!< cpu) audit(AUDIT_ARCH_NOT, "aarch64", cpu);

var flag = 0;

var pkgs = [
  "python3-unbound-1.17.1-10.h21510.6.eulerosv2r15",
  "unbound-help-1.17.1-10.h21510.6.eulerosv2r15",
  "unbound-libs-1.17.1-10.h21510.6.eulerosv2r15"
];

foreach (var pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"15", reference:pkg)) 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, "unbound");
}