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CVE-2016-6439· NVD / CVE Program· CNA cisco

A vulnerability in the detection engine reassembly of HTTP packets for Cisco Firepower System Software before 6.0.1 could allow an unauthent

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.

HighCVSS 7.5 · v3.0—No exploit No fix recorded
Published
Oct 27, 2016
Updated
Jun 16, 2026
EPSS
1.6% · 75th percentile
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Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.6%

Affected systems

VendorProduct
ciscosecure firewall management center

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cisco secure firewall management center5.3.0
  • cisco secure firewall management center5.3.0.2
  • cisco secure firewall management center5.3.0.3
  • cisco secure firewall management center5.3.0.4
  • cisco secure firewall management center5.3.1
  • cisco secure firewall management center5.3.1.3
  • cisco secure firewall management center5.3.1.4
  • cisco secure firewall management center5.3.1.5
  • cisco secure firewall management center5.3.1.6
  • cisco secure firewall management center5.4_base
  • cisco secure firewall management center5.4.0
  • cisco secure firewall management center5.4.0.2
  • cisco secure firewall management center5.4.1
  • cisco secure firewall management center5.4.1.1
  • cisco secure firewall management center5.4.1.2
  • cisco secure firewall management center5.4.1.3
  • cisco secure firewall management center5.4.1.4
  • cisco secure firewall management center5.4.1.5
  • cisco secure firewall management center5.4.1.6
  • cisco secure firewall management center6.0_base

Versions reported by the vendor

Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a Cisco Firepower System Software before 6.0.1

    • Cisco Firepower System Software before 6.0.1affected

Same product

cisco: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-20079Cisco Secure Firewall Management Center Authentication Bypass Remote Code Execution VulnerabilityKEV
    96Now
  • CVE-2026-20131Cisco Secure Firewall Management Center Software Remote Code Execution VulnerabilityKEV
    83Now
  • CVE-2026-20316Cisco Secure Firewall Management Center Software Static Credential VulnerabilityKEV
    62This week
  • CVE-2016-6433The Threat Management Console in Cisco Firepower Management Center 5.2.0 through 6.0.1 allows remote authenticated users to execute arbitrar
    59Plan
  • CVE-2025-20265Cisco Secure Firewall Management Center Software Radius Remote Code Execution Vulnerability
    45Plan
  • CVE-2023-20048A vulnerability in the web services interface of Cisco Firepower Management Center (FMC) Software could allow an authenticated, remote attac
    44Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-399 · Resource Management Errors

CVSS vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records