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CVE-2016-6366

97
FAUCET Score

CVE-2016-6366 is a critical buffer overflow vulnerability in Cisco Adaptive Security Appliance (ASA) Software, affecting various ASA devices, PIX, and FWSM. It allows remote authenticated attackers to execute arbitrary code via crafted IPv4 SNMP packets. With a CVSS score of 8.8 (HIGH) and a FAUCET Risk Score of 100/100, this vulnerability presents a significant threat due to its network-based attack vector, low complexity, and high impact on confidentiality, integrity, and availability. Notably, this flaw, also known as EXTRABACON, is actively exploited in the wild and has publicly available exploit code, including Metasploit modules and ExploitDB entries. The vulnerability has garnered substantial community discussion and media coverage, highlighting its widespread recognition and the urgency of patching.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:o:cisco:pix_firewall_software:-:*:*:*:*:*:*:*
>= 7.2.1, < 9.0.4.40CPE matchmatch criteria
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
>= 9.1.1, < 9.1.7\(9\)CPE matchmatch criteria
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
>= 9.2.0, < 9.2.4\(14\)CPE matchmatch criteria
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
>= 9.3.0, < 9.3.3\(10\)CPE matchmatch criteria
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
87.56%
Probability of exploitation in next 30 days
EPSS Percentile
99.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
Added to KEV · May 24, 2022
ExploitDB: EDB-40258 · Aug 18, 2016
This CVE's current EPSS score of 0.8757 is in the 100th percentile among its peer group of 17,808 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

ciscovendor investigatingvia nvd_reference
View patch

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
blogs.cisco.com / security/shadow-brokers
ExploitPress/Media CoverageVendor Advisory
github.com / offensive-security/exploit-database-bin-sploits/raw/master/sploits/40258.zip
Broken LinkExploit
exploit-db.com / exploits/40258
Third Party AdvisoryVDB Entry
zerosum0x0.blogspot.com / 2016/09/reverse-engineering-cisco-asa-for.html
ExploitTechnical Description
tools.cisco.com / security/center/content/CiscoSecurityAdvisory/cisco-sa-20160817-asa-snmp
Vendor Advisory
tools.cisco.com / security/center/viewErp.x
Vendor Advisory
securityfocus.com / bid/92521
Broken LinkNot ApplicableThird Party AdvisoryVDB Entry
securitytracker.com / id/1036637
Broken LinkThird Party AdvisoryVDB Entry