CVE-2016-6366

Buffer overflow in Cisco Adaptive Security Appliance (ASA) Software through 9.4.2.3 on ASA 5500,...

8.8 HighIn KEVPublic exploit

Buffer overflow in Cisco Adaptive Security Appliance (ASA) Software through 9.4.2.3 on ASA 5500, ASA 5500-X, ASA Services Module, ASA 1000V, ASAv, Firepower 9300 ASA Security Module, PIX, and FWSM devices allows remote authenticated users to execute arbitrary code via crafted IPv4 SNMP packets, aka Bug ID CSCva92151 or EXTRABACON.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

87.6%Down 4.2 points since Feb 4, 2022

What each source reports

NVD Score used 8.8

Record: CVE-2016-6366
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 8.5 HighAV:N/AC:M/Au:S/C:C/I:C/A:C
Weakness: CWE-120
Updated: 2026-11-02

CVE List 8.8

Record: CVE-2016-6366
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-120
Updated: 2026-11-02

EUVDEUVD-2016-7289 8.8

Record: EUVD-2016-7289
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-pfgh-2mw6-962h 8.8

Buffer overflow in Cisco Adaptive Security Appliance (ASA) Software through 9.4.2.3 on ASA 5500,...

Record: GHSA-pfgh-2mw6-962h
CVSS 3.0: 8.8 HighCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-119, CWE-120
Updated: 2026-11-02

CISA KEV No score

Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow Vulnerability

A buffer overflow vulnerability in the Simple Network Management Protocol (SNMP) code of Cisco ASA software could allow an attacker to cause a reload of the affected system or to remotely execute code.

Record: CVE-2016-6366
Weakness: CWE-119
Updated: 2026-11-02

Affected products

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
Exploit-DB	Cisco ASA 8.x - 'EXTRABACON' Authentication Bypass	2016-08-18
PoC in GitHub	RiskSense-Ops/CVE-2016-6366	2016-09-20
Metasploit	Cisco ASA Authentication Bypass (EXTRABACON)

History

History
Recorded	Changed	Sources
Nov 3, 2026	exploitation, exploits
Nov 2, 2026	first indexed	CVE List, EUVD, Exploit-DB, GitHub Advisories, CISA KEV, Metasploit, NVD, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2016-6366 is a high vulnerability (CVSS 8.8) in Cisco Adaptive Security Appliance (asa), published August 18, 2016. CISA lists it as known to be exploited, since May 24, 2022. EUVD reports exploitation since May 24, 2022. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 87.6%, the 99th percentile. No source names a fixed version.

References

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