Vulnerability Database

326,214

Total vulnerabilities in the database

CVE-2025-20155

A vulnerability in the bootstrap loading of Cisco IOS XE Software could allow an authenticated, local attacker to write arbitrary files to an affected system.

This vulnerability is due to insufficient input validation of the bootstrap file that is read by the system software when a device is first deployed in SD-WAN mode or when an administrator configures SD-Routing on the device. An attacker could exploit this vulnerability by modifying a bootstrap file generated by Cisco Catalyst SD-WAN Manager, loading it into the device flash, and then either reloading the device in a green field deployment in SD-WAN mode or configuring the device with SD-Routing. A successful exploit could allow the attacker to perform arbitrary file writes to the underlying operating system.

  • Published: May 7, 2025
  • Updated: Nov 16, 2025
  • CVE: CVE-2025-20155
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6
  • AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Software From Fixed in
cisco / ios_xe 17.11.99sw 17.11.99sw.x
cisco / ios_xe 17.13.1a 17.13.1a.x
cisco / ios_xe 17.13.1 17.13.1.x
cisco / ios_xe 17.12.1y 17.12.1y.x
cisco / ios_xe 17.12.2a 17.12.2a.x
cisco / ios_xe 17.12.3 17.12.3.x
cisco / ios_xe 17.9.4 17.9.4.x
cisco / ios_xe 17.9.5 17.9.5.x
cisco / ios_xe 17.9.4a 17.9.4a.x
cisco / ios_xe 17.9.5a 17.9.5a.x
cisco / ios_xe 17.9.5b 17.9.5b.x
cisco / ios_xe 17.12.1 17.12.1.x
cisco / ios_xe 17.12.1w 17.12.1w.x
cisco / ios_xe 17.12.1a 17.12.1a.x
cisco / ios_xe 17.12.1x 17.12.1x.x
cisco / ios_xe 17.12.2 17.12.2.x
cisco / ios_xe 17.12.4 17.12.4.x
cisco / ios_xe 17.14.1a 17.14.1a.x
cisco / ios_xe 17.9.6 17.9.6.x
cisco / ios_xe 17.9.6a 17.9.6a.x
cisco / ios_xe 17.9.5e 17.9.5e.x
cisco / ios_xe 17.9.5f 17.9.5f.x
cisco / ios_xe 17.12.1z 17.12.1z.x
cisco / ios_xe 17.12.3a 17.12.3a.x
cisco / ios_xe 17.12.1z1 17.12.1z1.x
cisco / ios_xe 17.12.4a 17.12.4a.x
cisco / ios_xe 17.12.4b 17.12.4b.x
cisco / ios_xe 17.14.1 17.14.1.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.