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Fencer Intel
high 8.8

CVE-2016-6366 kev in the critical feed json

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…

published 2016-08-18 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-7289

cvss
8.8
version 3.1, CNA
cisa kev
Exploited
added 2022-05-24
epss
87.6%
EPSS 87.6% chance of exploitation in 30 days, percentile 99.7%
public exploits
2
Metasploit, Exploit-DB

Summary

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.

Patch / fix

cisa required action Apply updates per vendor instructions.

  • cisco adaptive_security_appliance_software 9.0.4.40, 9.1.7\(9\), 9.2.4\(14\), 9.3.3\(10\), 9.4.3\(8\), 9.6.1\(11\)

Timeline

  1. Found exploited as a 0-day (Project Zero)
  2. 0-day patched (Project Zero)
  3. First public exploit (EDB-40258)
  4. Published
  5. Added to CISA KEV
  6. CISA patch deadline
  7. CISA SSVC: exploitation active

Known exploited

Added
4 y ago
Patch by
2022-06-14 (4 y ago)
Ransomware
Not known
Required action
Apply updates per vendor instructions.
Vendor, product
Cisco, Adaptive Security Appliance (ASA)
CISA name
Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow Vulnerability

Zero-day

Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.

Found
2016-08-15
Patched
2016-08-17
Details
project zero tracker

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

87.56% chance of exploitation in the next 30 days, higher than 99.7% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • Metasploit auxiliary/admin/networking/cisco_asa_extrabacon Cisco ASA Authentication Bypass (EXTRABACON) metasploit auxiliary, normal rank
  • EDB-40258 Cisco ASA 8.x - 'EXTRABACON' Authentication Bypass remote, 2016-08-18
  • github.com https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/40258.zip referenced PoC, tagged "exploit" by a source, unverified
  • blogs.cisco.com http://blogs.cisco.com/security/shadow-brokers referenced PoC, tagged "exploit" by a source, unverified
  • zerosum0x0.blogspot.com https://zerosum0x0.blogspot.com/2016/09/reverse-engineering-cisco-asa-for.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 8.5 AV:N/AC:M/Au:S/C:C/I:C/A:C

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.