CVE-2025-45286

Step 1: Payload Delivery: The attacker crafts a malicious payload containing JavaScript code (e.g., <script>alert('XSS')</script>). Step 2: Request Submission: The attacker submits the crafted payload to a vulnerable endpoint within httpbin v2.17.1, likely through a GET or POST request. The specific endpoint depends on the vulnerable functionality within httpbin. Step 3: Server-Side Processing: The httpbin application receives the request and processes the input, potentially storing or echoing the attacker's payload. Step 4: Response Generation: The application generates an HTTP response that includes the attacker's payload without proper sanitization or encoding. Step 5: Client-Side Execution: The victim's web browser receives the response containing the malicious JavaScript. The browser then executes the JavaScript code within the context of the httpbin domain, allowing the attacker to perform actions on behalf of the victim.

The vulnerability stems from insufficient input validation and output encoding within the httpbin application. Specifically, the application fails to properly sanitize user-supplied input before rendering it in the response. This allows an attacker to inject malicious JavaScript code within HTML tags, which is then executed by the victim's browser. The root cause is likely a missing or inadequate implementation of HTML encoding or input sanitization on user-provided data, specifically within the response generation logic. This allows for the injection of arbitrary HTML and JavaScript, leading to the execution of attacker-controlled code within the context of the vulnerable website. The lack of proper escaping of special characters like < and > is the core issue.