Vulnerability Database

353,909

Total vulnerabilities in the database

CVE-2020-13959 — apache / velocity_tools

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The default error page for VelocityView in Apache Velocity Tools prior to 3.1 reflects back the vm file that was entered as part of the URL. An attacker can set an XSS payload file as this vm file in the URL which results in this payload being executed. XSS vulnerabilities allow attackers to execute arbitrary JavaScript in the context of the attacked website and the attacked user. This can be abused to steal session cookies, perform requests in the name of the victim or for phishing attacks.

CVSS v3:

  • Severity: Medium
  • Score: 6.1
  • AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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.