Vulnerability Database

326,214

Total vulnerabilities in the database

CVE-2025-20140

A vulnerability in the Wireless Network Control daemon (wncd) of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, adjacent wireless attacker to cause a denial of service (DoS) condition.

This vulnerability is due to improper memory management. An attacker could exploit this vulnerability by sending a series of IPv6 network requests from an associated wireless IPv6 client to an affected device. To associate a client to a device, an attacker may first need to authenticate to the network, or associate freely in the case of a configured open network. A successful exploit could allow the attacker to cause the wncd process to consume available memory and eventually cause the device to stop responding, resulting in a DoS condition.

  • Published: May 7, 2025
  • Updated: Nov 16, 2025
  • CVE: CVE-2025-20140
  • Severity: High
  • Exploit:

CVSS v3:

  • Severity: High
  • Score: 7.4
  • AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CWEs:

Software From Fixed in
cisco / ios_xe 16.4.1 16.4.1.x
cisco / ios_xe 16.4.2 16.4.2.x
cisco / ios_xe 16.4.3 16.4.3.x
cisco / ios_xe 16.5.1 16.5.1.x
cisco / ios_xe 16.5.1a 16.5.1a.x
cisco / ios_xe 16.5.1b 16.5.1b.x
cisco / ios_xe 16.5.2 16.5.2.x
cisco / ios_xe 16.5.3 16.5.3.x
cisco / ios_xe 16.6.1 16.6.1.x
cisco / ios_xe 16.6.2 16.6.2.x
cisco / ios_xe 16.6.3 16.6.3.x
cisco / ios_xe 16.6.4 16.6.4.x
cisco / ios_xe 16.6.4a 16.6.4a.x
cisco / ios_xe 16.6.5 16.6.5.x
cisco / ios_xe 16.6.5a 16.6.5a.x
cisco / ios_xe 16.6.6 16.6.6.x
cisco / ios_xe 16.6.7 16.6.7.x
cisco / ios_xe 16.6.8 16.6.8.x
cisco / ios_xe 16.6.9 16.6.9.x
cisco / ios_xe 16.6.10 16.6.10.x
cisco / ios_xe 16.7.1 16.7.1.x
cisco / ios_xe 16.7.1a 16.7.1a.x
cisco / ios_xe 16.7.1b 16.7.1b.x
cisco / ios_xe 16.7.2 16.7.2.x
cisco / ios_xe 16.7.3 16.7.3.x
cisco / ios_xe 16.7.4 16.7.4.x
cisco / ios_xe 16.8.1 16.8.1.x
cisco / ios_xe 16.8.1a 16.8.1a.x
cisco / ios_xe 16.8.1b 16.8.1b.x
cisco / ios_xe 16.8.1c 16.8.1c.x
cisco / ios_xe 16.8.1d 16.8.1d.x
cisco / ios_xe 16.8.1e 16.8.1e.x
cisco / ios_xe 16.8.1s 16.8.1s.x
cisco / ios_xe 16.8.2 16.8.2.x
cisco / ios_xe 16.8.3 16.8.3.x
cisco / ios_xe 16.9.1 16.9.1.x
cisco / ios_xe 16.9.1a 16.9.1a.x
cisco / ios_xe 16.9.1b 16.9.1b.x
cisco / ios_xe 16.9.1s 16.9.1s.x
cisco / ios_xe 16.9.2 16.9.2.x
cisco / ios_xe 16.9.3 16.9.3.x
cisco / ios_xe 16.9.3a 16.9.3a.x
cisco / ios_xe 16.9.4 16.9.4.x
cisco / ios_xe 16.9.5 16.9.5.x
cisco / ios_xe 16.9.5f 16.9.5f.x
cisco / ios_xe 16.9.6 16.9.6.x
cisco / ios_xe 16.9.7 16.9.7.x
cisco / ios_xe 16.9.8 16.9.8.x
cisco / ios_xe 16.10.1 16.10.1.x
cisco / ios_xe 16.10.1a 16.10.1a.x
cisco / ios_xe 16.10.1b 16.10.1b.x
cisco / ios_xe 16.10.1c 16.10.1c.x
cisco / ios_xe 16.10.1d 16.10.1d.x
cisco / ios_xe 16.10.1e 16.10.1e.x
cisco / ios_xe 16.10.1f 16.10.1f.x
cisco / ios_xe 16.10.1g 16.10.1g.x
cisco / ios_xe 16.10.1s 16.10.1s.x
cisco / ios_xe 16.10.2 16.10.2.x
cisco / ios_xe 16.10.3 16.10.3.x
cisco / ios_xe 16.11.1 16.11.1.x
cisco / ios_xe 16.11.1a 16.11.1a.x
cisco / ios_xe 16.11.1b 16.11.1b.x
cisco / ios_xe 16.11.1s 16.11.1s.x
cisco / ios_xe 16.11.2 16.11.2.x
cisco / ios_xe 16.12.1 16.12.1.x
cisco / ios_xe 16.12.1a 16.12.1a.x
cisco / ios_xe 16.12.1c 16.12.1c.x
cisco / ios_xe 16.12.1s 16.12.1s.x
cisco / ios_xe 16.12.1t 16.12.1t.x
cisco / ios_xe 16.12.1w 16.12.1w.x
cisco / ios_xe 16.12.1x 16.12.1x.x
cisco / ios_xe 16.12.1y 16.12.1y.x
cisco / ios_xe 16.12.1z1 16.12.1z1.x
cisco / ios_xe 16.12.1z2 16.12.1z2.x
cisco / ios_xe 16.12.2 16.12.2.x
cisco / ios_xe 16.12.2a 16.12.2a.x
cisco / ios_xe 16.12.2s 16.12.2s.x
cisco / ios_xe 16.12.3 16.12.3.x
cisco / ios_xe 16.12.3a 16.12.3a.x
cisco / ios_xe 16.12.3s 16.12.3s.x
cisco / ios_xe 16.12.4 16.12.4.x
cisco / ios_xe 16.12.4a 16.12.4a.x
cisco / ios_xe 16.12.5 16.12.5.x
cisco / ios_xe 16.12.5a 16.12.5a.x
cisco / ios_xe 16.12.5b 16.12.5b.x
cisco / ios_xe 16.12.6 16.12.6.x
cisco / ios_xe 16.12.6a 16.12.6a.x
cisco / ios_xe 16.12.7 16.12.7.x
cisco / ios_xe 16.12.8 16.12.8.x
cisco / ios_xe 16.12.9 16.12.9.x
cisco / ios_xe 16.12.10 16.12.10.x
cisco / ios_xe 16.12.10a 16.12.10a.x
cisco / ios_xe 16.12.11 16.12.11.x
cisco / ios_xe 16.12.12 16.12.12.x
cisco / ios_xe 17.1.1 17.1.1.x
cisco / ios_xe 17.1.1a 17.1.1a.x
cisco / ios_xe 17.1.1s 17.1.1s.x
cisco / ios_xe 17.1.1t 17.1.1t.x
cisco / ios_xe 17.1.3 17.1.3.x
cisco / ios_xe 17.2.1 17.2.1.x
cisco / ios_xe 17.2.1a 17.2.1a.x
cisco / ios_xe 17.2.1r 17.2.1r.x
cisco / ios_xe 17.2.1v 17.2.1v.x
cisco / ios_xe 17.2.2 17.2.2.x
cisco / ios_xe 17.2.3 17.2.3.x
cisco / ios_xe 17.3.1 17.3.1.x
cisco / ios_xe 17.3.1a 17.3.1a.x
cisco / ios_xe 17.3.1w 17.3.1w.x
cisco / ios_xe 17.3.1x 17.3.1x.x
cisco / ios_xe 17.3.1z 17.3.1z.x
cisco / ios_xe 17.3.2 17.3.2.x
cisco / ios_xe 17.3.2a 17.3.2a.x
cisco / ios_xe 17.3.3 17.3.3.x
cisco / ios_xe 17.3.4 17.3.4.x
cisco / ios_xe 17.3.4a 17.3.4a.x
cisco / ios_xe 17.3.4b 17.3.4b.x
cisco / ios_xe 17.3.4c 17.3.4c.x
cisco / ios_xe 17.3.5 17.3.5.x
cisco / ios_xe 17.3.5a 17.3.5a.x
cisco / ios_xe 17.3.5b 17.3.5b.x
cisco / ios_xe 17.3.6 17.3.6.x
cisco / ios_xe 17.3.7 17.3.7.x
cisco / ios_xe 17.3.8 17.3.8.x
cisco / ios_xe 17.3.8a 17.3.8a.x
cisco / ios_xe 17.4.1 17.4.1.x
cisco / ios_xe 17.4.1a 17.4.1a.x
cisco / ios_xe 17.4.1b 17.4.1b.x
cisco / ios_xe 17.4.2 17.4.2.x
cisco / ios_xe 17.4.2a 17.4.2a.x
cisco / ios_xe 17.5.1 17.5.1.x
cisco / ios_xe 17.5.1a 17.5.1a.x
cisco / ios_xe 17.6.1 17.6.1.x
cisco / ios_xe 17.6.1a 17.6.1a.x
cisco / ios_xe 17.6.1w 17.6.1w.x
cisco / ios_xe 17.6.1x 17.6.1x.x
cisco / ios_xe 17.6.1y 17.6.1y.x
cisco / ios_xe 17.6.1z 17.6.1z.x
cisco / ios_xe 17.6.1z1 17.6.1z1.x
cisco / ios_xe 17.6.2 17.6.2.x
cisco / ios_xe 17.6.3 17.6.3.x
cisco / ios_xe 17.6.3a 17.6.3a.x
cisco / ios_xe 17.6.4 17.6.4.x
cisco / ios_xe 17.6.5 17.6.5.x
cisco / ios_xe 17.6.5a 17.6.5a.x
cisco / ios_xe 17.6.6 17.6.6.x
cisco / ios_xe 17.6.6a 17.6.6a.x
cisco / ios_xe 17.6.7 17.6.7.x
cisco / ios_xe 17.6.8 17.6.8.x
cisco / ios_xe 17.6.8a 17.6.8a.x
cisco / ios_xe 17.7.1 17.7.1.x
cisco / ios_xe 17.7.1a 17.7.1a.x
cisco / ios_xe 17.7.1b 17.7.1b.x
cisco / ios_xe 17.7.2 17.7.2.x
cisco / ios_xe 17.8.1 17.8.1.x
cisco / ios_xe 17.8.1a 17.8.1a.x
cisco / ios_xe 17.9.1 17.9.1.x
cisco / ios_xe 17.9.1a 17.9.1a.x
cisco / ios_xe 17.9.1w 17.9.1w.x
cisco / ios_xe 17.9.1x 17.9.1x.x
cisco / ios_xe 17.9.1x1 17.9.1x1.x
cisco / ios_xe 17.9.1y 17.9.1y.x
cisco / ios_xe 17.9.1y1 17.9.1y1.x
cisco / ios_xe 17.9.2 17.9.2.x
cisco / ios_xe 17.9.2a 17.9.2a.x
cisco / ios_xe 17.9.3 17.9.3.x
cisco / ios_xe 17.9.3a 17.9.3a.x
cisco / ios_xe 17.9.4 17.9.4.x
cisco / ios_xe 17.9.4a 17.9.4a.x
cisco / ios_xe 17.9.5 17.9.5.x
cisco / ios_xe 17.9.5a 17.9.5a.x
cisco / ios_xe 17.9.5b 17.9.5b.x
cisco / ios_xe 17.9.5e 17.9.5e.x
cisco / ios_xe 17.9.5f 17.9.5f.x
cisco / ios_xe 17.10.1 17.10.1.x
cisco / ios_xe 17.10.1a 17.10.1a.x
cisco / ios_xe 17.10.1b 17.10.1b.x
cisco / ios_xe 17.11.1 17.11.1.x
cisco / ios_xe 17.11.1a 17.11.1a.x
cisco / ios_xe 17.11.99sw 17.11.99sw.x
cisco / ios_xe 17.12.1 17.12.1.x
cisco / ios_xe 17.12.1a 17.12.1a.x
cisco / ios_xe 17.12.1w 17.12.1w.x
cisco / ios_xe 17.12.1x 17.12.1x.x
cisco / ios_xe 17.12.1y 17.12.1y.x
cisco / ios_xe 17.12.1z 17.12.1z.x
cisco / ios_xe 17.12.1z1 17.12.1z1.x
cisco / ios_xe 17.12.2 17.12.2.x
cisco / ios_xe 17.12.2a 17.12.2a.x
cisco / ios_xe 17.12.3 17.12.3.x
cisco / ios_xe 17.12.3a 17.12.3a.x
cisco / ios_xe 17.13.1 17.13.1.x
cisco / ios_xe 17.13.1a 17.13.1a.x
cisco / ios_xe 17.14.1 17.14.1.x
cisco / ios_xe 17.14.1a 17.14.1a.x

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.