A vulnerability in the Cisco Discovery Protocol (formerly known as CDP) subsystem of devices running, or based on, Cisco NX-OS Software contain a vulnerability that could allow an unauthenticated, adjacent attacker to create a denial of service (DoS) condition. The vulnerability is due to a failure to properly validate certain fields within a Cisco Discovery Protocol message prior to processing it. An attacker with the ability to submit a Cisco Discovery Protocol message designed to trigger the issue could cause a DoS condition on an affected device while the device restarts. This vulnerability affects Firepower 4100 Series Next-Generation Firewall, Firepower 9300 Security Appliance, MDS 9000 Series Multilayer Director Switches, Nexus 1000V Series Switches, Nexus 1100 Series Cloud Services Platforms, Nexus 2000 Series Switches, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 3600 Platform Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, UCS 6100 Series Fabric Interconnects, UCS 6200 Series Fabric Interconnects, UCS 6300 Series Fabric Interconnects. Cisco Bug IDs: CSCvc89242, CSCve40943, CSCve40953, CSCve40965, CSCve40970, CSCve40978, CSCve40992, CSCve41000, CSCve41007.
| Software | From | Fixed in |
|---|---|---|
| cisco / nx-os | 7.1 | 7.1\(5\)n1\(1\) |
| cisco / nx-os | 7.3 | 7.3\(3\)n1\(1\) |
| cisco / nx-os | 6.0 | 6.0.x |
| cisco / nx-os | 7.0 | 7.0.x |
| cisco / nx-os | 7.2 | 7.2.x |
| cisco / nx-os | 6.2 | 6.2\(20\) |
| cisco / nx-os | 7.2 | 7.2\(2\)d1\(3\) |
| cisco / nx-os | 7.3 | 7.3\(2\)d1\(1\) |
| cisco / nx-os | 8.1 | 8.1\(2\) |
| cisco / nx-os | 8.2 | 8.2\(1\) |
| cisco / nx-os | 8.0 | 8.0.x |
| cisco / nx-os | - | 7.0\(3\)i3 |
| cisco / nx-os | 7.0\(3\)i4 | 7.0\(3\)i7\(1\) |
| cisco / nx-os | - | 7.0\(3\)i7\(1\) |
| cisco / nx-os | 6.0 | 7.3\(3\)n1\(1\) |
| cisco / nx-os | 5.2 | 8.1\(1a\) |
| cisco / nx-os | - | 2.2\(8g\) |
| cisco / nx-os | 2.5 | 3.1\(2f\) |
| cisco / fxos | 2.2.2 | 2.2.2.14 |
| cisco / fxos | 1.1 | 2.0.1.152 |
| cisco / firepower_extensible_operating_system | 1.1 | 2.0.1.153 |
| cisco / firepower_extensible_operating_system | 2.1.1 | 2.1.1.86 |
| cisco / firepower_extensible_operating_system | 2.2.1 | 2.2.1.70 |
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.