CVE-2020-27478

The vulnerability exists in SimplCommerce v.40734964b0811f3cbaf64b6dac261683d256f961 through 3103357200c70b4767986544e01b19dbf11505a7. The search bar, which serves as a product filter, does not validate or sanitize user input before rendering it in the page. The application uses @Html.Raw to output user-supplied data directly, allowing HTML and script elements to be interpreted by the browser [1]. This results in a reflected cross-site scripting (XSS) condition.

An attacker can exploit this flaw by crafting a malicious URL containing a script payload, such as alert('s1nj0r0'), and tricking a victim into clicking the link. The attack requires no special privileges and can be executed remotely. The lack of input processing means the malicious script is injected into the HTML response without any encoding or sanitization [1].

Successful exploitation allows the attacker to execute arbitrary JavaScript in the context of the victim's session. This could lead to session hijacking, defacement, or theft of sensitive information displayed on the page. The CVSS v3 base score of 7.1 reflects the high impact on confidentiality and integrity, though the attack requires user interaction (e.g., clicking the crafted link).

The advisory recommends sanitizing user-supplied data and replacing @Html.Raw with safer alternatives like @Html.Encode(), though it notes that encoding alone may not cover all XSS attack vectors [1]. A permanent fix involves implementing proper input validation and output encoding to prevent injection of executable scripts.