CVE-2016-6439

What it is

A vulnerability in the detection engine reassembly of HTTP packets for Cisco Firepower System Software before 6.0.1 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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

1.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2016-10-27 21:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 00:51 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.6% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2016-10-27 21:59 UTC

Last modified

2026-06-17 00:51 UTC

Exploit probability

1.6% · EPSS, next 30 days

Weakness

CWE-399

Record status

Modified

Affected

• Cisco Secure Firewall Management Center 5.3.0
• Cisco Secure Firewall Management Center 5.3.0.2
• Cisco Secure Firewall Management Center 5.3.0.3
• Cisco Secure Firewall Management Center 5.3.0.4
• Cisco Secure Firewall Management Center 5.3.1
• Cisco Secure Firewall Management Center 5.3.1.3
• Cisco Secure Firewall Management Center 5.3.1.4
• Cisco Secure Firewall Management Center 5.3.1.5

Attack profile CVSS 3.0 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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