GHSA-m5f5-28qr-9g9r: prestashop/ps_facetedsearch: PHP Object Injection in faceted search cache allows unauthenticated RCE

Impact 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. Who is impacted Any shop using a vulnerable version of ps_facetedsearch that displays a filter template containing a slider filter (price or weight). Exploitation is remote and unauthenticated, a single crafted front-office request is enough, and leads to remote code execution and full compromise of the shop and its server. Affected versions: 3.0.0 through 4.0.3 (all versions since 3.0.0, including the latest release). Patches Upgrade the ps_facetedsearch module to the patched version. Upgrading the module is the best action that removes the vulnerability. Otherwise, you can apply the fix manually in the file src/Filters/Block.php: In the getFromCache() method, replace the native unserialize() call: // Before if (!empty($row)) { return unserialize(current($row)); } // After if (!empty($row)) { return \Tools::unSerialize(current($row)); } Until the module is upgraded: - Remove price and weight slider filters from the filter templates that are exposed on the front office. - Clear the faceted-search filter cache, and audit the modules/ps_facetedsearch/ directory for unexpected PHP files. - Monitor search requests for PHP serialization patterns (O:, ;i:, references to classes such as Monolog\…) and block them at the WAF level. Resources - Thank you to Frédéric Moreau (Antadis) and Gilles Caudal (Datalinx) for reporting this