CVE-2026-42635 in Simple Auctions Plugin
Summary
by MITRE • 10/06/2026
Unauthenticated Cross Site Scripting (XSS) in WooCommerce Simple Auctions <= 3.0.10 versions.
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as an unauthenticated cross-site scripting flaw within the WooCommerce Simple Auctions plugin, affecting versions up to and including 3.0.10, represents a significant security risk for WordPress-based e-commerce environments that utilize auction functionality. This specific type of web application vulnerability arises from insufficient sanitization or validation of user-supplied input before it is included in output sent to users' browsers. In the context of this plugin, attackers can inject malicious scripts into pages viewed by other users without needing valid authentication credentials. The absence of an access control requirement for the vulnerable endpoint means that any internet-facing visitor with knowledge of the specific URL or parameter structure associated with the auction feature can exploit this weakness, lowering the barrier to entry significantly compared to authenticated attacks.
From a technical perspective, cross-site scripting occurs when an application incorporates untrusted data into its output without properly neutralizing special characters that have meaning in HTML and JavaScript contexts. In WooCommerce Simple Auctions, certain parameters related to bid submissions or auction status updates likely fail to escape user input correctly. When the browser processes this injected content, it executes the malicious script as if it were part of the legitimate page source code generated by the server. This execution context is particularly dangerous because scripts run with the same privileges and permissions as trusted scripts on the site, allowing them to access cookies, session tokens, local storage, and other sensitive data associated with the user's current session against the target domain.
The operational impact of this vulnerability extends beyond simple script execution. Attackers can leverage unauthenticated XSS to perform account takeover attacks by stealing administrative or customer session cookies, thereby gaining unauthorized control over accounts without knowing passwords. Furthermore, malicious scripts can be used to deface websites, redirect users to phishing sites designed to harvest credentials, or distribute malware through drive-by downloads if the injected script interacts with browser vulnerabilities. For e-commerce platforms running WooCommerce Simple Auctions, this compromises not only user privacy but also the integrity of auction processes and financial transactions. The trust relationship between the website and its visitors is fundamentally broken, potentially leading to reputational damage and loss of customer confidence in the platform's security posture.
This vulnerability aligns with Common Weakness Enumeration (CWE) ID 79, which classifies Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. It also maps directly to MITRE ATT&CK technique T1059, specifically sub-technique T1059.007 for JavaScript execution within web browsers. The unauthenticated nature of the exploit places it in a high-risk category because it does not require prior compromise or social engineering to gain initial access beyond basic network connectivity and knowledge of the target URL structure.
Mitigation strategies must focus on immediate remediation through software updates and long-term defensive coding practices. Administrators running affected versions should upgrade WooCommerce Simple Auctions to version 3.0.11 or later, where this input validation issue has been addressed by developers implementing proper escaping functions for all user inputs rendered in HTML contexts. For organizations unable to patch immediately due to compatibility constraints, temporary mitigations may include deploying a Web Application Firewall configured with rulesets capable of detecting and blocking XSS payloads based on signature patterns. Additionally, enforcing Content Security Policy headers can restrict the execution of inline scripts and limit the domains from which resources are loaded, thereby reducing the impact even if an injection attempt succeeds. Regular security audits and code reviews focusing on input validation and output encoding are essential to prevent similar vulnerabilities in future development cycles.