CVE-2026-3891 Scanner

The Pix for WooCommerce plugin is widely used by online retailers using WordPress to facilitate transactions via Pix, a popular payment method in Brazil. It helps in easing the payment process by integrating Pix into WooCommerce sites, thereby streamlining operations for web-based businesses. Typically adopted by small to medium-sized enterprises, it enhances the site's functionality, making it more versatile in catering to diverse customer payment preferences. Businesses benefit from its easy integration which allows them to manage payments directly from their WordPress dashboard. Retailers adopting the solution aim to provide a seamless payment experience, which in turn can help improve customer satisfaction and retention. However, maintaining the current version is crucial for security and optimal performance.

The unauthenticated arbitrary file upload vulnerability allows attackers to upload files to the server without authentication, bypassing standard security measures. This occurs due to missing capability checks and file type validation in the plugin's code. It can lead to serious security implications, including remote code execution, allowing attackers to run malicious code on the server. The vulnerability is particularly severe due to its ease of exploitation, given that it requires no prior authentication. Ensuring proper access control and file validation mechanisms are necessary to mitigate this risk. As such, users of affected systems need to deploy a suitable fix or update immediately.

Technically, this vulnerability resides in the 'lkn_pix_for_woocommerce_c6_save_settings' function within the plugin's settings handling. Attackers can craft a specially formatted request containing arbitrary files to this endpoint, exploiting the lack of validation. The absent capability checks in the plugin's code fail to ensure that only authorized users can perform sensitive actions, which leaves the door open for misuse. The use of improperly checked input in constructing paths for file storage further grants attackers unintended access. This issue can result in the creation of executable files on the server, which can be leveraged to execute arbitrary commands. The process through which files are uploaded lacks strict enforcement, amplifying the risk of exploitation.

Exploiting this vulnerability can have devastating effects, including full server compromise. Attackers can upload and execute arbitrary scripts, potentially leading to data theft, defacement, or other malicious activities. In a worse-case scenario, this could result in total business disruption, financial losses, and reputational damage. Particularly, remote code execution is an alarming consequence, as it enables attackers to run commands with the privileges of the web server user. This could further extend to escalated privileges if additional security flaws exist. Therefore, threats like data breaches or misuse of the site for hosting malicious content are plausible.

REFERENCES

• https://github.com/m4sh-wacker/CVE-2026-3891-Pix-for-WooCommerce-Plugin-Exploit
• https://wordpress.org/plugins/payment-gateway-pix-for-woocommerce/