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

• Packagist prestashop/ps_facetedsearch: >= 3.0.0, < 4.0.4 → fixed in 4.0.4

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: ```php // 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 vulnerability.