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,
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.
- Published
- Aug 18, 2016
- Updated
- Jun 16, 2026
- EPSS
- 87.6% · 100th percentile
- CWE
- CWE-120
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Action score
91
Now
Patch today or shut off access.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 26 / 30 · 87.6%
CISA SSVC decision
- Exploitation
- active
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on May 24, 2022. That signals real attacks, not theory.
Remediation deadline for government agencies: Jun 14, 2022.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | pix firewall software | cpe:2.3:o:cisco:pix_firewall_software |
| cisco | pix firewall 501 | cpe:2.3:h:cisco:pix_firewall_501 |
| cisco | pix firewall 506 | cpe:2.3:h:cisco:pix_firewall_506 |
| cisco | pix firewall 506e | cpe:2.3:h:cisco:pix_firewall_506e |
| cisco | pix firewall 515 | cpe:2.3:h:cisco:pix_firewall_515 |
| cisco | pix firewall 515e | cpe:2.3:h:cisco:pix_firewall_515e |
| cisco | pix firewall 520 | cpe:2.3:h:cisco:pix_firewall_520 |
| cisco | pix firewall 525 | cpe:2.3:h:cisco:pix_firewall_525 |
| cisco | pix firewall 535 | cpe:2.3:h:cisco:pix_firewall_535 |
| cisco | adaptive security appliance software | cpe:2.3:o:cisco:adaptive_security_appliance_software |
| cisco | 7604 | cpe:2.3:h:cisco:7604 |
| cisco | 7606-s | cpe:2.3:h:cisco:7606-s |
and 33 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco adaptive security appliance software7.2.1 and later · before 9.0.4.40
- cisco adaptive security appliance software9.1.1 and later · before 9.1.7\(9\)
- cisco adaptive security appliance software9.2.0 and later · before 9.2.4\(14\)
- cisco adaptive security appliance software9.3.0 and later · before 9.3.3\(10\)
- cisco adaptive security appliance software9.4.0.115 and later · before 9.4.3\(8\)
- cisco adaptive security appliance software9.5.0 and later · up to 9.5\(3\) inclusive
- cisco adaptive security appliance software9.6.0 and later · before 9.6.1\(11\)
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2000-1022The mailguard feature in Cisco Secure PIX Firewall 5.2(2) and earlier does not properly restrict access to SMTP commands, which allows remot32Monitor
- CVE-2002-2139Cisco PIX Firewall 6.0.3 and earlier, and 6.1.x to 6.1.3, do not delete the duplicate ISAKMP SAs for a user's VPN session, which allows loca25Monitor
- CVE-2002-2140Buffer overflow in Cisco PIX Firewall 5.2.x to 5.2.8, 6.0.x to 6.0.3, 6.1.x to 6.1.3, and 6.2.x to 6.2.1 allows remote attackers to cause a 21Monitor
- CVE-2000-1027Cisco Secure PIX Firewall 5.2(2) allows remote attackers to determine the real IP address of a target FTP server by flooding the server with21Monitor
- CVE-1999-0158Cisco PIX firewall manager (PFM) on Windows NT allows attackers to connect to port 8080 on the PFM server and retrieve any file whose name a20Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
- Exploit-DB entry ×1
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | remote | 2016-08-18 |
| Metasploit module | auxiliary/admin/networking/cisco_asa_extrabaconCisco ASA Authentication Bypass (EXTRABACON)auxiliary | — |
| Proof-of-concept repository on GitHub | stars:163 | 2016-09-20 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-1 d
- Published
- CISA KEV+2104 d
- TodaySep 30, 2026+3695 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.
The bug in code
The whole CWE-120 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
char buf[256];memcpy(buf, pkt->data, pkt->len);Fixed
char buf[256];if (pkt->len > sizeof(buf)) { return -EINVAL;}memcpy(buf, pkt->data, pkt->len);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
- Overflow Variables and TagsCAPEC-46likelihood: High · High
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160817-asa-snmp
- tools.cisco.com/security/center/viewErp.x?alertId=ERP-56516
- www.securityfocus.com/bid/92521
- www.securitytracker.com/id/1036637
- www.exploit-db.com/exploits/40258/
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-6366
Vendor advisories and official records. Exploit/PoC links are deliberately left out.