CWE-93 (对CRLF序列的转义处理不恰当(CRLF注入)) — Vulnerability Class 89

CWE-93 represents a critical input validation weakness where applications fail to properly sanitize Carriage Return and Line Feed characters within user-supplied data. This vulnerability typically enables attackers to inject malicious HTTP headers or split response lines, facilitating attacks such as HTTP response splitting, session fixation, or cross-site scripting. By manipulating these control characters, adversaries can alter the structure of web responses, potentially redirecting users to phishing sites or injecting malicious scripts into the browser context. To mitigate this risk, developers must rigorously validate and sanitize all input fields, specifically filtering out or encoding CRLF sequences before processing. Implementing strict allow-lists for acceptable characters and utilizing framework-provided encoding functions ensures that these control characters are neutralized, thereby preserving the integrity of HTTP headers and preventing unauthorized manipulation of application logic.