VDB-93000 · CVE-2016-6439 · BID 93787

Cisco ASA on 5500-X Firepower Detection Engine HTTP resource management

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability, which was classified as critical, was found in Cisco ASA on 5500-X (Firewall Software). Affected is an unknown code block of the component Firepower Detection Engine. The manipulation as part of a HTTP leads to a resource management vulnerability. CWE is classifying the issue as CWE-399. This is going to have an impact on availability.

The weakness was published 10/19/2016 with Cisco as cisco-sa-20161019-fpsnort / CSCux61630 as confirmed advisory (Website). The advisory is shared for download at tools.cisco.com. This vulnerability is traded as CVE-2016-6439 since 07/26/2016. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The advisory points out:

A vulnerability in the detection engine reassembly of HTTP packets for Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to the Snort process unexpectedly restarting. The vulnerability is due to improper handling of an HTTP packet stream. An attacker could exploit this vulnerability by sending a crafted HTTP packet stream to the detection engine on the targeted device. An exploit could allow the attacker to cause a DoS condition if the Snort process restarts and traffic inspection is bypassed or traffic is dropped.

The vulnerability scanner Nessus provides a plugin with the ID 94469 (Cisco Firepower Packet Inspection Engine HTTP Stream DoS), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CISCO and running in the context l.

Upgrading eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (94469). Further details are available at tools.cisco.com. Similar entries are available at 92999 and 92998.

Not Affected

  • Cisco ASA
  • Cisco Firepower Management Center
  • CIsco IPS Software
  • Snort IPS for Integrated Services Routers








  • end of life (old version)

CPE 2.3info

CPE 2.2info


VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍


VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍



VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍


Class: Resource management
CWE: CWE-399 / CWE-404
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 94469
Nessus Name: Cisco Firepower Packet Inspection Engine HTTP Stream DoS
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 881575
OpenVAS Name: Cisco Firepower Detection Engine HTTP Denial of Service Vulnerability
OpenVAS File: 🔍
OpenVAS Family: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍


07/26/2016 🔍
10/19/2016 +85 days 🔍
10/19/2016 +0 days 🔍
10/19/2016 +0 days 🔍
10/19/2016 +0 days 🔍
10/20/2016 +1 days 🔍
10/27/2016 +7 days 🔍
11/02/2016 +6 days 🔍
09/28/2022 +2156 days 🔍


Vendor: cisco.com

Advisory: cisco-sa-20161019-fpsnort / CSCux61630
Organization: Cisco
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2016-6439 (🔍)
SecurityTracker: 1037061
SecurityFocus: 93787 - Multiple Cisco Products CVE-2016-6439 Denial of Service Vulnerability

Misc.: 🔍
See also: 🔍


Created: 10/20/2016 09:01 AM
Updated: 09/28/2022 08:49 AM
Changes: 10/20/2016 09:01 AM (75), 05/14/2019 04:42 PM (12), 09/28/2022 08:49 AM (3)
Complete: 🔍


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