PrestaShop ps_facetedsearch is a module that adds layered navigation filters. From 3.0.0 until 4.0.4, the ps_facetedsearch module rebuilds selected search filters from the request URL, and the value of a slider filter, price or weight, is taken from the URL without sufficient validation and stored in an internal filter-block cache where it is serialized and later read back with a raw native unserialize() in src/Filters/Block.php. By crafting that value, an unauthenticated attacker can smuggle a malicious serialized PHP object into the cache, and when it is deserialized, a gadget chain writes an arbitrary PHP file inside the modules/ps_facetedsearch/ directory, which is then used as a webshell to run commands on the server. This issue is fixed in version 4.0.4.

Affected: Packagist: prestashop/ps_facetedsearch

### 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 i…