CVE-2023-30786 in Captcha Them All Plugin
Summary
by MITRE • 08/16/2023
Auth. (admin+) Stored Cross-Site Scripting (XSS) vulnerability in Benjamin Guy Captcha Them All plugin <= 1.3.3 versions.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/28/2026
This vulnerability represents a stored cross-site scripting flaw that exists within the Benjamin Guy Captcha Them All WordPress plugin affecting versions 1.3.3 and earlier. The issue stems from inadequate input validation and output escaping mechanisms within the plugin's administrative interface where user-supplied data is not properly sanitized before being stored in the database and subsequently rendered back to users. The vulnerability specifically affects administrators and users with administrative privileges who can manipulate the plugin's configuration settings through the WordPress admin panel. When malicious scripts are injected through the affected input fields and subsequently displayed to other users who access the compromised pages, the malicious code executes within their browser context, potentially enabling attackers to steal session cookies, perform unauthorized actions, or redirect users to malicious sites.
The technical implementation of this vulnerability aligns with CWE-79 which describes improper neutralization of input during web page generation in a web application. This weakness allows attackers to inject malicious scripts that persist in the application's database, making it a stored XSS variant rather than a reflected one. The vulnerability's impact is amplified by the administrative privilege requirements, as attackers must first compromise an administrator account or gain sufficient access to manipulate the plugin settings. The ATT&CK framework categorizes this as a technique under T1566 - Phishing, where the malicious scripts can be used to harvest credentials or perform other malicious activities. The vulnerability exists because the plugin fails to implement proper sanitization routines when processing user inputs from administrative forms, particularly when handling configuration parameters that are later rendered in web pages without adequate context-specific escaping.
The operational implications of this vulnerability extend beyond simple script execution as it provides attackers with a persistent foothold within the WordPress environment. Once exploited, attackers can leverage the stored XSS to perform actions such as modifying plugin configurations, injecting additional malicious code, or using the compromised administrator session to access other parts of the WordPress installation. The vulnerability is particularly concerning because it requires only administrative access to be exploited, meaning that if an attacker can obtain administrative credentials through other means such as credential stuffing, brute force attacks, or social engineering, they can immediately deploy this XSS payload. The persistent nature of stored XSS means that the malicious code will continue to execute whenever affected pages are accessed, potentially affecting multiple users over extended periods.
Mitigation strategies for this vulnerability should focus on immediate remediation through plugin updates to versions that address the XSS flaw, typically version 1.3.4 or later. Organizations should implement comprehensive input validation and output escaping mechanisms that follow secure coding practices, particularly when handling user-supplied data in administrative contexts. The principle of least privilege should be enforced by ensuring that only necessary users have administrative access to WordPress installations, reducing the attack surface for such vulnerabilities. Regular security audits of WordPress plugins should include checks for proper input sanitization and output escaping, particularly in administrative interfaces. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against XSS attacks by restricting the sources from which scripts can be executed, though this should not be considered a replacement for proper input validation. Network monitoring solutions should be configured to detect unusual patterns in plugin configuration changes that might indicate exploitation attempts.