CVE-2016-6367
CVE-2016-6367 is a security flaw in Cisco Adaptive Security Appliance (ASA), Cisco’s firewall. Someone who already has a way in can use Cisco Adaptive Security Appliance (ASA) to run their own code. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 24 May 2022.[1]
Cisco Adaptive Security Appliance (ASA) is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff.
Description
CISA calls it a CLI remote code execution in Cisco Adaptive Security Appliance (ASA). In its words: “A vulnerability in the command-line interface (CLI) parser of Cisco ASA software could allow an authenticated, local attacker to create a denial-of-service (DoS) condition or potentially execute code.”[1]
The underlying weakness is command injection (CWE-77), in MITRE’s list of common software weaknesses.[2]
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it. CISA names the product as Cisco Adaptive Security Appliance (ASA).
Most families won’t have Cisco Adaptive Security Appliance (ASA); it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 24 May 2022, 2,105 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 14 Jun 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 23%. That’s in the top 3% of the flaws it scores.[3]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Cisco Adaptive Security Appliance (ASA) is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 14 Jun 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 23%.[3] |
See also
Other Cisco Adaptive Security Appliance (ASA) flaws
- CVE-2014-2120: cross-site scripting (XSS) ·
- CVE-2016-6366: SNMP buffer overflow ·
- CVE-2018-0296: denial-of-service ·
Other Cisco flaws
- CVE-2026-76418, Cisco Secure Firewall ASA Software and Cisco Secure FTD Software: unchecked return value to NULL pointer dereference ·
- CVE-2026-76519, Cisco Secure Email Gateway: relative path traversal ·
- CVE-2026-76504, Cisco Catalyst SD-WAN Manager: hex encoding ·
- CVE-2026-76460, Cisco Identity Services Engine: incorrect use of privileged APIs ·
- CVE-2026-76461, Cisco Secure Email Gateway: SQL injection ·
Other command injection flaws
- CVE-2026-105134, AhsayCBS: command injection ·
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2016-3081, Apache Struts: command injection ·
- CVE-2026-8037, Progress LoadMaster: command injection ·
- CVE-2025-29635, D-Link DIR-823X: command injection ·
Added the same day
- CVE-2018-8611, Microsoft Windows: kernel privilege escalation ·
- CVE-2018-19953, QNAP Network Attached Storage (NAS): NAS file station cross-site scripting ·
- CVE-2018-19949, QNAP Network Attached Storage (NAS): NAS file station command injection ·
- CVE-2018-19943, QNAP Network Attached Storage (NAS): NAS file station cross-site scripting ·
- CVE-2017-8543, Microsoft Windows: search remote code execution ·
Every Cisco flaw on CISA’s list · Everything added in May 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution Vulnerability”. Known Exploited Vulnerabilities Catalog, added 24 May 2022.
- ^ National Institute of Standards and Technology. “CVE-2016-6367 Detail”. National Vulnerability Database, published 18 Aug 2016.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.226, percentile 97.7, 31 Oct 2026.
- CVE Program. “CVE-2016-6367”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.