Jinja2 SSTI WAF Bypass

I recently sumbled onto a CTF chall that required SSTI and bypass the "WAF". The app.py looked like this: from werkzeug.urls import url_fix from secrets import token_urlsafe from flask import Flask, request, render_template, redirect, url_for app = Flask(__name__) @app.route("/") def index(): return render_template("index.html", error=request.args.get("error")) @app.route("/new", methods=["POST"]) def create(): content = request.form.get("content", "") if "_" in... » read more