Vulnerability Database

393,392

Total vulnerabilities in the database

CVE-2019-1758 — cisco / ios

Improper Authentication

A vulnerability in 802.1x function of Cisco IOS Software on the Catalyst 6500 Series Switches could allow an unauthenticated, adjacent attacker to access the network prior to authentication. The vulnerability is due to how the 802.1x packets are handled in the process path. An attacker could exploit this vulnerability by attempting to connect to the network on an 802.1x configured port. A successful exploit could allow the attacker to intermittently obtain access to the network.

  • Published: Mar 28, 2019
  • Updated: Oct 3, 2026
  • CVE: CVE-2019-1758
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 4.7
  • AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS v2:

  • Severity: Low
  • Score: 3.3
  • AV:A/AC:L/Au:N/C:N/I:P/A:N
Software Affected versions
cisco / ios = 12.2(33)sxj6
cisco / ios = 12.2(33)sxj7
cisco / ios = 12.2(33)sxj8
cisco / ios = 12.2(33)sxj9
cisco / ios = 12.2(33)sxj10
cisco / ios = 12.2(60)ez12
cisco / ios = 15.1(1)sy1
cisco / ios = 15.1(1)sy2
cisco / ios = 15.1(1)sy3
cisco / ios = 15.1(1)sy4
cisco / ios = 15.1(1)sy5
cisco / ios = 15.1(1)sy6
cisco / ios = 15.1(2)sg8a
cisco / ios = 15.1(2)sy
cisco / ios = 15.1(2)sy1
cisco / ios = 15.1(2)sy2
cisco / ios = 15.1(2)sy3
cisco / ios = 15.1(2)sy4
cisco / ios = 15.1(2)sy4a
cisco / ios = 15.1(2)sy5
cisco / ios = 15.1(2)sy6
cisco / ios = 15.1(2)sy7
cisco / ios = 15.1(2)sy8
cisco / ios = 15.1(2)sy9
cisco / ios = 15.1(2)sy10
cisco / ios = 15.1(2)sy11
cisco / ios = 15.1(2)sy12
cisco / ios = 15.1(2)sy13
cisco / ios = 15.1(3)svg3d
cisco / ios = 15.1(3)svi1b
cisco / ios = 15.1(3)svk4b
cisco / ios = 15.1(3)svk4c
cisco / ios = 15.1(3)svm3
cisco / ios = 15.1(3)svn2
cisco / ios = 15.1(3)svo1
cisco / ios = 15.1(3)svo2
cisco / ios = 15.1(3)svp1
cisco / ios = 15.1(3)svp2
cisco / ios = 15.1(4)m12c
cisco / ios = 15.2(1)sy
cisco / ios = 15.2(1)sy0a
cisco / ios = 15.2(1)sy1
cisco / ios = 15.2(1)sy1a
cisco / ios = 15.2(1)sy2
cisco / ios = 15.2(1)sy3
cisco / ios = 15.2(1)sy4
cisco / ios = 15.2(1)sy5
cisco / ios = 15.2(1)sy6
cisco / ios = 15.2(1)sy7
cisco / ios = 15.2(2)sy
cisco / ios = 15.2(2)sy1
cisco / ios = 15.2(2)sy2
cisco / ios = 15.2(2)sy3
cisco / ios = 15.2(3)ea1
cisco / ios = 15.2(4)jn1
cisco / ios = 15.2(4a)ea5
cisco / ios = 15.3(0)sy
cisco / ios = 15.3(1)sy
cisco / ios = 15.3(1)sy1
cisco / ios = 15.3(1)sy2
cisco / ios = 15.3(3)ja1n
cisco / ios = 15.3(3)jf35
cisco / ios = 15.3(3)ji2
cisco / ios = 15.4(1)sy
cisco / ios = 15.4(1)sy1
cisco / ios = 15.4(1)sy2
cisco / ios = 15.4(1)sy3
cisco / ios = 15.4(1)sy4
cisco / ios = 15.5(1)sy
cisco / ios = 15.5(1)sy1
cisco / ios = 15.5(1)sy2
cisco / ios = 15.6(2)sp3b

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.