Language: Java
Label: vulnerable
CWE: CWE-79 \u2014 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Code:
	public <A extends Output<E>, E extends Exception> void append(A a, char c) throws E {
		switch (c) {
			case '&' -> {
				a.append(AMP);
			}
			case '<' -> {
				a.append(LT);
			}
			case '>' -> {
				a.append(GT);
			}
			case '"' -> {
				a.append(QUOT);
			}
			default -> {
				a.append(c);
			}
		}
	}