F5 Networks BIG-IP : NLnet Labs Unbound vulnerability (K000162456)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from F5 Networks BIG-IP Solution K000162456.
#
# @NOAGENT@
##

include('compat.inc');

if (description)
{
  script_id(330218);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/27");

  script_cve_id("CVE-2026-41292", "CVE-2026-42944");

  script_name(english:"F5 Networks BIG-IP : NLnet Labs Unbound vulnerability (K000162456)");

  script_set_attribute(attribute:"synopsis", value:
"The remote device is missing a vendor-supplied security patch.");
  script_set_attribute(attribute:"description", value:
"The version of F5 Networks BIG-IP installed on the remote host is prior to tested version. It is, therefore, affected by
multiple vulnerabilities as referenced in the K000162456 advisory.

    CVE-2026-41292NLnet 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-2026-42944NLnet 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.

Tenable has extracted the preceding description block directly from the F5 Networks BIG-IP 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://my.f5.com/manage/s/article/K000162456");
  script_set_attribute(attribute:"solution", value:
"The vendor has acknowledged the vulnerability, but no solution has been provided.
Refer to the vendor for remediation guidance.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:U/C:N/I:N/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: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-2026-42944");

  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:"plugin_publication_date", value:"2026/07/27");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_domain_name_system");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:f5:big-ip_global_traffic_manager");
  script_set_attribute(attribute:"cpe", value:"cpe:/h:f5:big-ip");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"F5 Networks Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("f5_bigip_detect.nbin");
  script_require_keys("Host/local_checks_enabled", "Host/BIG-IP/hotfix", "Host/BIG-IP/modules", "Host/BIG-IP/version", "Settings/ParanoidReport");

  exit(0);
}


include('f5_func.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var version = get_kb_item('Host/BIG-IP/version');
if ( ! version ) audit(AUDIT_OS_NOT, 'F5 Networks BIG-IP');
if ( isnull(get_kb_item('Host/BIG-IP/hotfix')) ) audit(AUDIT_KB_MISSING, 'Host/BIG-IP/hotfix');
if ( ! get_kb_item('Host/BIG-IP/modules') ) audit(AUDIT_KB_MISSING, 'Host/BIG-IP/modules');

if (report_paranoia < 2) audit(AUDIT_PARANOID);

var sol = 'K000162456';
var vmatrix = {
  'DNS': {
    'affected': [
      '21.0.0-21.1.0','17.5.0-17.5.1','17.1.0-17.1.3'
    ],
  }
};

if (bigip_is_affected(vmatrix:vmatrix, sol:sol))
{
  var extra = NULL;
  if (report_verbosity > 0) extra = bigip_report_get();
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : extra
  );
}
else
{
  var tested = bigip_get_tested_modules();
  var audit_extra = 'For BIG-IP module(s) ' + tested + ',';
  if (tested) audit(AUDIT_INST_VER_NOT_VULN, audit_extra, version);
  else audit(AUDIT_HOST_NOT, 'running the affected module DNS');
}