Vulnerability Database

393,392

Total vulnerabilities in the database

CVE-2016-6391 — cisco / ios

Resource Management Errors

Cisco IOS 12.2 and 15.0 through 15.3 allows remote attackers to cause a denial of service (traffic-processing outage) via a crafted series of Common Industrial Protocol (CIP) requests, aka Bug ID CSCur69036.

  • Published: Oct 5, 2016
  • Updated: Oct 3, 2026
  • CVE: CVE-2016-6391
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v2:

  • Severity: High
  • Score: 7.8
  • AV:N/AC:L/Au:N/C:N/I:N/A:C

CWEs:

Software Affected versions
cisco / ios = 12.2(44)ex
cisco / ios = 12.2(44)ex1
cisco / ios = 12.2(46)se
cisco / ios = 12.2(46)se1
cisco / ios = 12.2(46)se2
cisco / ios = 12.2(50)se
cisco / ios = 12.2(50)se1
cisco / ios = 12.2(50)se2
cisco / ios = 12.2(50)se3
cisco / ios = 12.2(50)se4
cisco / ios = 12.2(50)se5
cisco / ios = 12.2(52)se
cisco / ios = 12.2(52)se1
cisco / ios = 12.2(55)se
cisco / ios = 12.2(55)se3
cisco / ios = 12.2(55)se4
cisco / ios = 12.2(55)se5
cisco / ios = 12.2(55)se6
cisco / ios = 12.2(55)se7
cisco / ios = 12.2(55)se8
cisco / ios = 12.2(55)se9
cisco / ios = 12.2(55)se10
cisco / ios = 12.2(58)se2
cisco / ios = 15.0(1)ey
cisco / ios = 15.0(1)ey1
cisco / ios = 15.0(1)ey2
cisco / ios = 15.0(2)eb
cisco / ios = 15.0(2)ey
cisco / ios = 15.0(2)ey1
cisco / ios = 15.0(2)ey2
cisco / ios = 15.0(2)ey3
cisco / ios = 15.0(2)se
cisco / ios = 15.0(2)se1
cisco / ios = 15.0(2)se2
cisco / ios = 15.0(2)se3
cisco / ios = 15.0(2)se4
cisco / ios = 15.0(2)se5
cisco / ios = 15.0(2)se6
cisco / ios = 15.0(2)se7
cisco / ios = 15.0(2)se9
cisco / ios = 15.2(1)ey
cisco / ios = 15.2(2)e
cisco / ios = 15.2(2)e1
cisco / ios = 15.2(2)e2
cisco / ios = 15.2(2)e4
cisco / ios = 15.2(3)ea
cisco / ios = 15.3(3)ja
cisco / ios = 15.3(3)ja1
cisco / ios = 15.3(3)ja1m
cisco / ios = 15.3(3)ja1n
cisco / ios = 15.3(3)ja4
cisco / ios = 15.3(3)ja5
cisco / ios = 15.3(3)ja7
cisco / ios = 15.3(3)ja8
cisco / ios = 15.3(3)ja9
cisco / ios = 15.3(3)ja77
cisco / ios = 15.3(3)jaa
cisco / ios = 15.3(3)jab
cisco / ios = 15.3(3)jax
cisco / ios = 15.3(3)jax1
cisco / ios = 15.3(3)jax2
cisco / ios = 15.3(3)jb
cisco / ios = 15.3(3)jb75
cisco / ios = 15.3(3)jbb
cisco / ios = 15.3(3)jbb1
cisco / ios = 15.3(3)jbb2
cisco / ios = 15.3(3)jbb4
cisco / ios = 15.3(3)jbb5
cisco / ios = 15.3(3)jbb6
cisco / ios = 15.3(3)jbb6a
cisco / ios = 15.3(3)jbb8
cisco / ios = 15.3(3)jbb50
cisco / ios = 15.3(3)jc
cisco / ios = 15.3(3)jn3
cisco / ios = 15.3(3)jn4
cisco / ios = 15.3(3)jn7
cisco / ios = 15.3(3)jn8
cisco / ios = 15.3(3)jnb
cisco / ios = 15.3(3)jnb1
cisco / ios = 15.3(3)jnb2
cisco / ios = 15.3(3)jnb3
cisco / ios = 15.3(3)jnc
cisco / ios = 15.3(3)jnc1
cisco / ios = 15.3(3)jnp
cisco / ios = 15.3(3)jnp1

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.