CVE-2026-54159: prestashop/ps_facetedsearch: PHP Object Injection in faceted search cache allows unauthenticated RCE

A PHP Object Injection vulnerability affects the PrestaShop module ps_facetedsearch.

The module rebuilds the selected search filters from the request URL. The value of a slider filter (price or weight) is taken from the URL without sufficient validation, then stored in an internal filter-block cache where it is serialized and later read back with a raw native unserialize(). By crafting that value, an attacker can smuggle a malicious serialized PHP object into the cache. When it is deserialized, a gadget chain writes an arbitrary PHP file inside the module directory, which is then used as a webshell to run commands on the server.