CVE-2026-1826 identifies a stored Cross-Site Scripting vulnerability in the OpenPOS Lite – Point of Sale for WooCommerce plugin for WordPress, present in all versions up to and including 3.0. The vulnerability stems from insufficient input sanitization and output escaping of the 'width' parameter used in the order_qrcode shortcode. This parameter is intended to control the size of a QR code displayed on order pages. However, because the plugin fails to properly neutralize malicious input, an authenticated attacker with Contributor-level access or higher can inject arbitrary JavaScript code that is stored persistently in the WordPress database. When any user, including administrators or customers, accesses the page containing the injected shortcode, the malicious script executes in their browser context. This can lead to session hijacking, theft of sensitive information, unauthorized actions on behalf of users, or further compromise of the WordPress site. The vulnerability requires no user interaction beyond visiting the affected page but does require the attacker to have at least Contributor privileges, which are commonly granted to content creators or editors. The CVSS 3.1 base score is 6.4, reflecting network attack vector, low attack complexity, privileges required, no user interaction, and partial confidentiality and integrity impact with no availability impact. No public exploits or patches are currently available, but the vulnerability has been publicly disclosed. The issue is classified under CWE-79, a common and well-understood web application security weakness. Given the widespread use of WooCommerce and WordPress in e-commerce, this vulnerability poses a significant risk to online retail environments using the affected plugin.

For European organizations, especially those in retail and e-commerce sectors using WooCommerce with the OpenPOS Lite plugin, this vulnerability can lead to unauthorized script execution in users' browsers. This compromises confidentiality by exposing session tokens or personal data, and integrity by allowing attackers to perform unauthorized actions such as modifying orders or injecting fraudulent content. Although availability is not directly impacted, the reputational damage and potential regulatory consequences under GDPR for data breaches could be severe. Attackers with Contributor-level access, which may be granted to many internal users or third-party contributors, can exploit this vulnerability without requiring further user interaction, increasing the risk of insider threats or compromised accounts being leveraged. The stored nature of the XSS means the malicious payload persists and affects all users accessing the infected pages, amplifying the attack surface. This can lead to widespread compromise of customer data and loss of trust in the affected e-commerce platforms.

Immediate mitigation involves restricting Contributor-level permissions to trusted users only, minimizing the number of accounts with such access. Organizations should monitor and audit user roles and capabilities regularly. Until an official patch is released, administrators can implement web application firewall (WAF) rules to detect and block malicious payloads targeting the 'width' parameter in the order_qrcode shortcode. Input validation and output encoding can be enforced at the application or server level as a temporary measure. Additionally, scanning the WordPress database for injected scripts and cleaning affected pages can reduce risk. Once a patch is available, prompt updating of the OpenPOS Lite plugin to a fixed version is critical. Employing Content Security Policy (CSP) headers to restrict script execution origins can further mitigate exploitation impact. Regular security training for users with elevated privileges can help prevent inadvertent exploitation. Finally, continuous monitoring for anomalous behavior or unauthorized changes in the WordPress environment is recommended.