High severityC#Cross-Site Scripting (XSS)MEDIUM confidence
Response Write Concatenation
A response body is assembled by concatenating/interpolating a runtime value and written without HTML encoding (CWE-79).
Standards mapping
- OWASP Top 10
- A03:2021 - Injection
- OWASP ASVS
- V5.3.3 (L1)
Vulnerable vs. safe
Flagged by this check
Response.Write($"<h1>{name}</h1>");Passes - the safe pattern
Response.Write("<h1>Welcome</h1>");Why it matters & how to fix it
A response body is assembled by concatenating/interpolating a runtime value and written without HTML encoding (CWE-79). Encode the value with HttpUtility.HtmlEncode / WebUtility.HtmlEncode before writing it, or render through a Razor view that auto-escapes output.
References
Rule ID integsec.csharp.xss.response-write-concat - engine: Opengrep - license: MIT - Copyright (c) IntegSec Inc.
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