CVE-2016-6366
HighExploitedPublic exploitBuffer 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…
Published Aug 18, 2016 · Updated Apr 22, 2026
Key Facts
Patch immediately- CVE-2016-6366 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Adaptive Security Appliance Software (Cisco), Asa 1000v Cloud Firewall Software (Cisco), Pix Firewall Software (Cisco).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 15, 2016. Public exploit code is available.
- EPSS estimates a 88% probability of exploitation in the next 30 days.
- Fixed versions are available, including Adaptive Security Appliance Software 9.0.4.40.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
88%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2016-6366 brief as a PDF
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Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | May 24, 2022 | Jun 14, 2022 | Not reported |
| Industry KEV feed | Aug 15, 2016 | Jun 14, 2022 | Not reported |
| CIRCL KEV | May 24, 2022 | Jun 14, 2022 | Not reported |
| ENISA EUVD | May 24, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
4 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Adaptive Security Appliance SoftwareCisco | See advisory | 9.0.4.40 |
| Asa 1000v Cloud Firewall SoftwareCisco | 8.7.1, 8.7.1.1 | n/a |
| Pix Firewall SoftwareCisco | See advisory | n/a |
Patched Releases
Adaptive Security Appliance Software
9.0.4.40
Timeline
Added to Industry KEV feed
Aug 15, 2016
Publicly disclosed
Aug 18, 2016
Added to CISA KEV
May 24, 2022
Added to CIRCL KEV
May 24, 2022
Added to ENISA EUVD
May 24, 2022
Last updated
Apr 22, 2026
Weakness Type
- CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
References
- advisory40258
- advisory20160817 Cisco Adaptive Security Appliance SNMP Remote Code Execution Vulnerability
- advisoryhttp://tools.cisco.com/security/center/viewErp.x?alertId=ERP-56516
- advisory92521
- advisory1036637
FAQ
Common Questions.
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 o…
Affected: Adaptive Security Appliance Software (Cisco); Asa 1000v Cloud Firewall Software (Cisco) versions 8.7.1, 8.7.1.1; Pix Firewall Software (Cisco). The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 15, 2016.
Yes. It was added on May 24, 2022 with a federal remediation due date of Jun 14, 2022.
Public exploit code is available.
Fixed versions are available, including Adaptive Security Appliance Software 9.0.4.40.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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