CVE-2026-62111 in Simple Payment Plugin
Summary
by MITRE • 09/11/2026
Contributor Cross Site Scripting (XSS) in Simple Payment <= 2.5.4 versions.
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Analysis
by VulDB Data Team • 09/11/2026
The vulnerability identified as Contributor Cross-Site Scripting within the Simple Payment plugin, affecting versions up to and including 2.5.4, represents a significant security risk for WordPress-based e-commerce environments. This flaw stems from insufficient input validation and output encoding mechanisms when handling user-supplied data associated with contributor roles or payment-related metadata. In typical web application architecture, cross-site scripting occurs when an attacker injects malicious client-side scripts into pages viewed by other users. In this specific context, the vulnerability allows a low-privilege user, such as a contributor, to execute arbitrary JavaScript in the browser of any victim who views the affected content. This is particularly dangerous because it exploits the trust that browsers have in content from the site, allowing the attacker to bypass same-origin policy restrictions and perform actions on behalf of authenticated users or steal sensitive information stored within cookies or local storage.
From a technical perspective, the root cause lies in how the plugin processes and renders data related to payment transactions or contributor profiles without properly sanitizing special characters that have meaning in HTML context. When user input is reflected directly into an HTML response without adequate encoding of entities such as less-than signs, greater-than signs, ampersands, quotes, and apostrophes, it enables the injection of script tags. The attacker can craft a payload containing JavaScript code, often disguised within seemingly benign fields like contributor names, payment notes, or transaction descriptions. When an administrator or another user with higher privileges views this data through the WordPress dashboard or public-facing pages where such information is displayed, the browser interprets and executes the injected script as part of the legitimate page content. This execution happens in the security context of the vulnerable website, granting the attacker elevated permissions relative to the victim's session.
The operational impact of this vulnerability extends beyond simple defacement or minor annoyance. Because Simple Payment handles financial transactions and contributor data, successful exploitation can lead to severe consequences including account takeover via cookie theft, where an attacker captures session cookies to impersonate administrators or high-level contributors. It also facilitates phishing attacks by redirecting users to malicious sites that mimic legitimate payment portals, thereby harvesting credentials. Furthermore, the ability to execute arbitrary JavaScript allows for keylogging, capturing sensitive data entered into forms on the same domain, and potentially modifying page content to display fraudulent payment instructions during active transactions. This undermines the integrity of financial records and erodes user trust in the platform's security posture. The vulnerability is classified under CWE-79, which covers Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting, highlighting the failure to neutralize special characters before rendering them in a web page context.
Mitigation strategies must address both immediate remediation and long-term defensive coding practices. The most effective solution is to upgrade the Simple Payment plugin to version 2.5.4 or later, where developers have presumably implemented proper input sanitization using functions like wp_kses_post or esc_html_ depending on the output context. For organizations unable to update immediately due to compatibility constraints, temporary mitigations include implementing a Web Application Firewall that can detect and block common XSS payloads in HTTP requests. Additionally, enforcing strict Content Security Policy headers can significantly reduce the impact of successful exploitation by restricting the sources from which scripts are allowed to load or execute. Developers should also adopt secure coding standards such as OWASP Top Ten guidelines, ensuring that all user inputs are validated against expected formats and encoded appropriately before being rendered in HTML attributes, text nodes, or JavaScript contexts. Regular security audits and penetration testing of payment plugins are essential to identify similar flaws in other components of the e-commerce stack.