A new cross-site scripting (XSS) vulnerability, identified as CVE-2023-5914, has recently been discovered by security researchers, posing a significant risk to web applications and their users. In this long read, we will take a closer look at this specific vulnerability, discuss its consequences, provide code snippets, and offer ways to remediate and prevent such issues in the future. By the end of this article, you should have a better understanding of the threat posed by XSS, especially within the context of CVE-2023-5914, and what can be done to protect your websites against such vulnerabilities.

CVE-2023-5914: The Details

CVE-2023-5914 involves a specific type of XSS vulnerability – stored (or persistent) XSS. Stored XSS attacks occur when malicious code gets permanently stored on the vulnerable web application server, typically in a database, and gets executed when a user visits the affected page. This makes stored XSS more dangerous than the other two types of XSS attacks – reflected XSS and DOM-based XSS – as it doesn't require any user interaction to execute the payload.

The exploit uses the lack of input validation and output encoding when handling user-generated content. When this content is displayed on the browser without proper sanitization, the attacker's malicious code is executed, potentially leading to several consequences such as data theft, session hijacking, and defacement of web applications.

Code Snippet

To make this more concrete, let's take a look at a simple code snippet that demonstrates this vulnerability:

<!DOCTYPE html>
    <h1>Welcome to our Guestbook</h1>
    <form action="submit.php" method="post">
      Enter your name: <input type="text" name="name">
      Leave your message: <textarea name="message"></textarea>
      <input type="submit" value="Submit">

    <!-- Display stored messages -->
      $mysqli = new mysqli("localhost", "user", "password", "guestbook");
      $result = $mysqli->query("SELECT * FROM messages");

      while ($row = $result->fetch_assoc()) {
        echo "<p><b>" . $row['name'] . " wrote:</b><br/>" . $row['message'] . "</p>";

This is a simple guestbook application where users can leave their names and messages. The stored messages are displayed on the page. However, this code is vulnerable to stored XSS because it does not sanitize or encode user input when displaying the messages.

An attacker might submit a message like this

<script>/*malicious code*/</script>

The malicious script will then be stored in the database and executed when users visit the guestbook page, potentially stealing their cookies or redirecting them to malicious websites.

Here are some reliable sources for detailed information on CVE-2023-5914

1. The official CVE database: CVE-2023-5914

2. The National Vulnerability Database (NVD) entry: CVE-2023-5914

Prevention and Remediation

The following steps can be taken to protect your web applications from XSS vulnerabilities like CVE-2023-5914:

1. Validate and sanitize user input: Ensure that user input adheres to the expected data format and remove any potentially malicious characters or code.

2. Encode output: When displaying user-generated content in the browser, always encode it to prevent the execution of malicious code. For example, use the htmlspecialchars() function in PHP to encode HTML special characters.

echo "<p><b>" . htmlspecialchars($row['name']) . " wrote:</b><br/>" . htmlspecialchars($row['message']) . "</p>";

3. Employ secure coding practices: Follow best practices and industry standards when developing and maintaining web applications to reduce the likelihood of security vulnerabilities.

4. Regularly scan and test your applications: Use automated tools and manual penetration testing to identify vulnerabilities and proactively address them.

5. Keep software up-to-date: Always apply the latest security patches and updates to the software and libraries used in your applications.


Cross-site scripting (XSS) vulnerabilities, like the recently discovered CVE-2023-5914, can compromise the security and privacy of your website's users. By following the preventative measures mentioned above and staying informed about new vulnerabilities, it is possible to significantly reduce the risk posed by XSS attacks and maintain a secure web environment.


Published on: 01/17/2024 21:15:11 UTC