CWE-83 (Web页面属性中脚本转义处理不恰当) — Vulnerability Class 19

CWE-83 represents a critical input validation weakness where web applications fail to properly sanitize dangerous attributes within HTML tags, such as onmouseover, onload, or style. Attackers typically exploit this vulnerability by injecting malicious JavaScript code directly into these attributes, bypassing standard content filters that only check the tag body. This allows for Cross-Site Scripting (XSS) attacks, enabling the execution of arbitrary scripts in the victim’s browser to steal session cookies, deface websites, or redirect users to phishing sites. To prevent this, developers must implement rigorous output encoding and strict input validation that specifically targets attribute values. Utilizing robust security libraries that automatically escape special characters and enforcing Content Security Policy headers further mitigates the risk by restricting the execution of unauthorized scripts, ensuring that user-supplied data remains inert within the DOM structure.