Overview

The Form Maker by 10Web WordPress plugin, before version 1.15.51, is vulnerable to a stored cross-site scripting (XSS) attack. This type of vulnerability occurs when user-submitted data is stored on the server and then rendered on a webpage without proper sanitization, allowing an attacker to inject malicious scripts. In this case, the vulnerability allows unauthenticated users to store a payload that executes as arbitrary web scripts in the session of an administrator who views the submissions. This can lead to unauthorized actions, data theft, or further exploitation within the WordPress environment.

Understanding the Vulnerability / Threat

Root Cause Analysis

The root cause of this vulnerability is the inconsistent escaping of user-submitted field values before rendering them on the submissions admin page of the Form Maker by 10Web WordPress plugin. This flaw falls under the CWE-79 category, which pertains to improper neutralization of input during web page generation, commonly known as cross-site scripting (XSS). The vulnerability arises from a design and implementation issue, as the plugin does not adequately sanitize or escape user-input data.

Attack Surface & Vector

This vulnerability is accessible over the network (AV:N) and requires no user interaction (UI:R) but does necessitate some complexity to exploit (AC:H). An attacker does not need any privileges (PR:N) to exploit this vulnerability. The attack vector involves submitting a crafted payload through the form, which is then stored and executed when an administrator views the submission. The scope of the vulnerability remains unchanged (S:U), meaning the exploitation does not affect other components beyond the plugin itself.

Exploitation Mechanics — Scenario Walkthrough

Scenario: Compromising a Corporate WordPress Instance via Form Maker

1. Initial Position: An attacker with access to the internet discovers a WordPress site using the Form Maker by 10Web plugin, version 1.15.50 or earlier.

2. Triggering the Flaw: The attacker crafts a malicious payload, typically a JavaScript snippet designed to perform an unauthorized action, and submits it through the form on the WordPress site. The payload could be designed to steal session cookies, perform actions as the administrator, or inject further malware.

3. What Breaks: When an administrator accesses the submissions page to view the form data, the malicious payload is executed within their session. This breaks the security boundary that should prevent unauthorized scripts from running on the administrator's page, allowing the attacker to perform actions they otherwise could not.

4. Attacker's Prize: Upon successful exploitation, the attacker could gain unauthorized access to perform administrative actions on the WordPress site. This could include creating new admin accounts, modifying site content, installing additional malicious plugins, or even pivoting to attack other parts of the network if the WordPress site has elevated privileges.

Real-World Impact

The impact of this vulnerability can be significant. An attacker could exploit it to gain administrative control over a WordPress site, leading to potential data breaches, website defacement, distribution of malware, or even lateral movement within a network if the compromised site has access to internal resources. Given that the vulnerability has a CVSS score of 7.5, it is considered high severity, emphasizing the need for prompt mitigation.

Detection & Defense

Immediate Mitigations

To address this vulnerability immediately, users of the Form Maker by 10Web plugin should upgrade to version 1.15.51 or later. This patch likely includes fixes to properly escape user-submitted data, preventing the injection of malicious scripts.

Detection Strategies

Defenders can detect exploitation attempts by monitoring for unusual patterns of submissions or anomalies in administrator sessions. Implementing a web application firewall (WAF) that can detect and block malicious scripts can also help. Additionally, keeping detailed logs of administrator actions and regularly reviewing them for suspicious activity can aid in early detection.

Long-Term Hardening

For long-term hardening against this class of vulnerabilities, it is essential to implement a robust content security policy (CSP) on the web server, regularly update and patch plugins and themes, and use secure coding practices. Employing a principle of least privilege, where administrators only have the access they need, can also limit the damage of a successful exploit. Regular security audits and penetration testing can help identify and mitigate potential vulnerabilities before they are exploited.

Key Takeaways

  • Stored XSS vulnerabilities can have a significant impact, allowing attackers to inject and execute malicious scripts in the context of other users.
  • Proper input sanitization and output encoding are crucial in preventing XSS attacks.
  • Regular updates and patches are essential to protect against known vulnerabilities in plugins and software.
  • A defense-in-depth approach, including WAFs, CSP, and monitoring, can help detect and prevent exploitation attempts.

Sources

  • National Vulnerability Database (NVD) - CVE-2026-105413
  • WPScan Vulnerability Database