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Cisco ASA Unrestricted Upload of File with Dangerous Type (CVE-2020-3436)

🗓️ 05 Oct 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com👁 4 Views

Unauthenticated remote attacker can upload files to Cisco ASA or FTD causing DoS.

Related
Refs
Code
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(506073);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/06");

  script_cve_id("CVE-2020-3436");

  script_name(english:"Cisco ASA Unrestricted Upload of File with Dangerous Type (CVE-2020-3436)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"A vulnerability in the web services interface of Cisco Adaptive
Security Appliance (ASA) and Cisco Firepower Threat Defense (FTD)
Software could allow an unauthenticated, remote attacker to upload
arbitrary-sized files to specific folders on an affected device, which
could lead to an unexpected device reload. The vulnerability exists
because the affected software does not efficiently handle the writing
of large files to specific folders on the local file system. An
attacker could exploit this vulnerability by uploading files to those
specific folders. A successful exploit could allow the attacker to
write a file that triggers a watchdog timeout, which would cause the
device to unexpectedly reload, causing a denial of service (DoS)
condition.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
  # https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-fileup-dos-zvC7wtys
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?565ae2af");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  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:C/C:N/I:N/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-2020-3436");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(434);

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/10/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/10/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/05");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:cisco:adaptive_security_appliance_software:9");
  script_set_attribute(attribute:"generated_plugin", value:"former");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Tenable.ot");

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

  script_dependencies("tenable_ot_api_integration.nasl");
  script_require_keys("Tenable.ot/Cisco");

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/Cisco');

var asset = tenable_ot::assets::get(vendor:'Cisco');

var vuln_cpes = {
    "cpe:/o:cisco:adaptive_security_appliance_software:9.8.0" :
        {"versionEndExcluding" : "9.8.4.25", "versionStartIncluding" : "9.8.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.9.0" :
        {"versionEndExcluding" : "9.9.2.80", "versionStartIncluding" : "9.9.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.10.0" :
        {"versionEndExcluding" : "9.10.1.44", "versionStartIncluding" : "9.10.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.12.0" :
        {"versionEndExcluding" : "9.12.4.2", "versionStartIncluding" : "9.12.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.13.0" :
        {"versionEndExcluding" : "9.13.1.12", "versionStartIncluding" : "9.13.0", "family" : "CiscoFirepower"},
    "cpe:/o:cisco:adaptive_security_appliance_software:9.14.0" :
        {"versionEndExcluding" : "9.14.1.15", "versionStartIncluding" : "9.14.0", "family" : "CiscoFirepower"}
};

tenable_ot::cve::compare_and_report(asset:asset, cpes:vuln_cpes, severity:SECURITY_HOLE);

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06 Oct 2026 00:00Current
6.1Medium risk
Vulners AI Score6.1
CVSS 27.8
CVSS 3.18.6
CVSS 38.6
EPSS0.01935
SSVC
4