CVE-2016-6366

HIGHNVD 8.89.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2022-05-24), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
8.8
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 88%CVSS: 8.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.8
EG Score
9.0(high)
EG Risk
—
EPSS
99.7%
KEV
⚠ Exploited

Published

August 18, 2016

Last Modified

April 22, 2026

Advisory Details (6)

Auto-updated May 2, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

Cisco Adaptive Security Appliance SNMP Remote Code Execution Vulnerability

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160817-asa-snmp
generic

The Shadow Brokers EPICBANANA and EXTRABACON Exploits - Cisco Blogs

http://blogs.cisco.com/security/shadow-brokers
generic

zerosum0x0: Reverse Engineering Cisco ASA for EXTRABACON Offsets

https://zerosum0x0.blogspot.com/2016/09/reverse-engineering-cisco-asa-for.html
generic🟡 PoC Available

Cisco ASA 8.x - 'EXTRABACON' Authentication Bypass - Hardware remote Exploit

https://www.exploit-db.com/exploits/40258/
generic
http://www.securityfocus.com/bid/92521
generic

Cisco Event Response: Cisco ASA and IOS Vulnerabilities

http://tools.cisco.com/security/center/viewErp.x?alertId=ERP-56516

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 54× in last 7d / 224× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 419 total refreshes for this CVE.

  1. 2026-07-22 22:03 UTCEG score recompute
  2. 2026-07-22 20:19 UTCGHSA enrichment
  3. 2026-07-22 19:40 UTCCISA KEV update
  4. 2026-07-22 16:26 UTCEG score recompute
  5. 2026-07-22 16:26 UTCGHSA enrichment
  6. 2026-07-22 14:04 UTCEPSS rescore
  7. 2026-07-22 12:40 UTCGHSA enrichment
  8. 2026-07-22 09:00 UTCGHSA enrichment
  9. 2026-07-22 05:18 UTCGHSA enrichment
  10. 2026-07-22 01:05 UTCGHSA enrichment
  11. 2026-07-21 19:49 UTCGHSA enrichment
  12. 2026-07-21 16:01 UTCGHSA enrichment
  13. 2026-07-21 14:37 UTCCISA KEV update
  14. 2026-07-21 12:20 UTCGHSA enrichment
  15. 2026-07-21 08:39 UTCGHSA enrichment
  16. 2026-07-21 04:58 UTCGHSA enrichment
  17. 2026-07-21 01:17 UTCGHSA enrichment
  18. 2026-07-20 21:36 UTCGHSA enrichment
  19. 2026-07-20 17:54 UTCGHSA enrichment
  20. 2026-07-20 14:14 UTCGHSA enrichment
  21. 2026-07-20 10:32 UTCGHSA enrichment
  22. 2026-07-20 06:52 UTCGHSA enrichment
  23. 2026-07-20 02:21 UTCGHSA enrichment
  24. 2026-07-19 22:40 UTCGHSA enrichment
  25. 2026-07-19 19:00 UTCGHSA enrichment
Show 75 more
  1. 2026-07-19 15:19 UTCEG score recompute
  2. 2026-07-19 15:19 UTCGHSA enrichment
  3. 2026-07-19 14:28 UTCEPSS rescore
  4. 2026-07-19 14:28 UTCEPSS rescore
  5. 2026-07-19 11:39 UTCGHSA enrichment
  6. 2026-07-19 07:58 UTCGHSA enrichment
  7. 2026-07-19 04:17 UTCGHSA enrichment
  8. 2026-07-19 00:36 UTCGHSA enrichment
  9. 2026-07-18 20:55 UTCGHSA enrichment
  10. 2026-07-18 17:14 UTCGHSA enrichment
  11. 2026-07-18 13:34 UTCGHSA enrichment
  12. 2026-07-18 09:52 UTCGHSA enrichment
  13. 2026-07-18 06:11 UTCGHSA enrichment
  14. 2026-07-18 02:31 UTCGHSA enrichment
  15. 2026-07-17 22:50 UTCGHSA enrichment
  16. 2026-07-17 19:10 UTCGHSA enrichment
  17. 2026-07-17 15:28 UTCGHSA enrichment
  18. 2026-07-17 11:47 UTCGHSA enrichment
  19. 2026-07-17 08:06 UTCEG score recompute
  20. 2026-07-17 08:06 UTCGHSA enrichment
  21. 2026-07-17 04:25 UTCGHSA enrichment
  22. 2026-07-17 00:44 UTCGHSA enrichment
  23. 2026-07-16 21:01 UTCGHSA enrichment
  24. 2026-07-16 17:19 UTCGHSA enrichment
  25. 2026-07-16 17:04 UTCCISA KEV update
  26. 2026-07-16 13:38 UTCGHSA enrichment
  27. 2026-07-16 09:58 UTCGHSA enrichment
  28. 2026-07-16 06:17 UTCGHSA enrichment
  29. 2026-07-16 02:33 UTCGHSA enrichment
  30. 2026-07-15 22:52 UTCGHSA enrichment
  31. 2026-07-15 19:12 UTCGHSA enrichment
  32. 2026-07-15 16:54 UTCEPSS rescore
  33. 2026-07-15 16:54 UTCEPSS rescore
  34. 2026-07-15 16:49 UTCCISA KEV update
  35. 2026-07-15 15:31 UTCGHSA enrichment
  36. 2026-07-15 15:04 UTCCISA KEV update
  37. 2026-07-15 11:50 UTCGHSA enrichment
  38. 2026-07-15 08:09 UTCGHSA enrichment
  39. 2026-07-15 04:28 UTCGHSA enrichment
  40. 2026-07-15 00:48 UTCGHSA enrichment
  41. 2026-07-14 21:08 UTCGHSA enrichment
  42. 2026-07-14 18:05 UTCCISA KEV update
  43. 2026-07-14 17:27 UTCGHSA enrichment
  44. 2026-07-14 13:47 UTCGHSA enrichment
  45. 2026-07-14 10:05 UTCGHSA enrichment
  46. 2026-07-14 06:24 UTCGHSA enrichment
  47. 2026-07-14 02:43 UTCGHSA enrichment
  48. 2026-07-13 23:03 UTCGHSA enrichment
  49. 2026-07-13 19:22 UTCGHSA enrichment
  50. 2026-07-13 17:07 UTCCISA KEV update
  51. 2026-07-13 15:41 UTCGHSA enrichment
  52. 2026-07-13 12:01 UTCGHSA enrichment
  53. 2026-07-13 08:20 UTCGHSA enrichment
  54. 2026-07-13 06:09 UTCEPSS rescore
  55. 2026-07-13 04:39 UTCGHSA enrichment
  56. 2026-07-13 00:59 UTCGHSA enrichment
  57. 2026-07-12 21:18 UTCGHSA enrichment
  58. 2026-07-12 17:37 UTCGHSA enrichment
  59. 2026-07-12 13:56 UTCGHSA enrichment
  60. 2026-07-12 10:16 UTCGHSA enrichment
  61. 2026-07-12 06:35 UTCGHSA enrichment
  62. 2026-07-12 05:43 UTCEPSS rescore
  63. 2026-07-12 05:43 UTCEPSS rescore
  64. 2026-07-12 02:54 UTCGHSA enrichment
  65. 2026-07-11 23:13 UTCGHSA enrichment
  66. 2026-07-11 19:33 UTCGHSA enrichment
  67. 2026-07-11 15:53 UTCGHSA enrichment
  68. 2026-07-11 12:12 UTCGHSA enrichment
  69. 2026-07-11 08:32 UTCGHSA enrichment
  70. 2026-07-11 08:24 UTCEPSS rescore
  71. 2026-07-11 04:52 UTCGHSA enrichment
  72. 2026-07-11 01:11 UTCGHSA enrichment
  73. 2026-07-10 21:30 UTCGHSA enrichment
  74. 2026-07-10 17:52 UTCCISA KEV update
  75. 2026-07-10 17:50 UTCGHSA enrichment

Publicly available exploits

(3 references)

Working exploit code is in the public domain (1 Metasploit module) (1 GitHub PoC) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCRiskSense-Ops/CVE-2016-6366
    First seen Sep 20, 2016

    Public repository for improvements to the EXTRABACON exploit

    Open source ↗
  • Exploit-DBEDB-40258
    First seen Aug 18, 2016

    Cisco ASA 8.x - 'EXTRABACON' Authentication Bypass

    Open source ↗
  • Metasploitauxiliary/admin/networking/cisco_asa_extrabacon✓ verified
    First seen Jan 1, 2016

    Cisco ASA Authentication Bypass (EXTRABACON)

    Open source ↗

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2016-6366?
CVE-2016-6366 is a high vulnerability published on August 18, 2016. 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…
When was CVE-2016-6366 disclosed?
CVE-2016-6366 was first published in the National Vulnerability Database on August 18, 2016, with the most recent update on April 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-6366 actively exploited?
Yes. CISA added CVE-2016-6366 to the Known Exploited Vulnerabilities catalog on May 24, 2022, affecting Cisco Adaptive Security Appliance (ASA). KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2016-6366?
CVE-2016-6366 has a CVSS v3 base score of 8.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2016-6366?
CVE-2016-6366 affects Cisco Adaptive Security Appliance (ASA). The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2016-6366?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-6366, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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