psd-tools is a Python package for working with Adobe Photoshop PSD files. Prior to version 1.17.1, `SmartObject.save()` writes an embedded smart object to a path taken verbatim from the PSD file. Because that name is attacker-controlled and unsanitised, a tool that extracts embedded objects from an untrusted `.psd` can be made to write attacker-chosen bytes to an attacker-chosen path (absolute or `../`-traversing), outside its intended output directory. A secondary issue in `SmartObject.open()` for external-kind smart objects allows the attacker-controlled `fullPath` descriptor to be used as an arbitrary file read path, enabling exfiltration of the read content to the controlled write destination. Both issues are fixed in v1.17.1.

Affected: PyPI: psd-tools

# psd-tools: arbitrary file write/read via smart-object path traversal

## Summary

In `psd-tools` (all releases exposing the `SmartObject` API through **v1.17.0**), `SmartObject.save()` writes an embedded smart object to a path taken verbatim from the PSD file. Because that name is attacker-controlled and unsanitised, a tool that extracts embedded objects from an untrusted `.psd` can be made to write attacker-chosen bytes to an attacker-chosen path (absolute or `../`-traversing), outside its intended output directory.

A secondary issue in `SmartObject.open()` for external-kind smart objects allows the attacker-controlled `fullPath` descriptor to be used as an arbitrary file **read** path, enabling exfiltration of the read content to the controlled write destination. Both issues are fixed in **v1.17.1**.

## Details

### Write path — `SmartObject.save()` (primary)

`src/psd_tools/api/smart_object.py:170-179` (tag `v1.17.0`):

```python def save(self, filename: str | None = None) -> None: if filename is None: filename = self.filename # untrusted, straight from the file with open(filename, "wb") as f: f.write(self.data) # attacker-controlled bytes ```

`self.filename` comes from the file with no validation — the `filename` property (`:62-67`) returns `self._data.filename`, set by the linked-layer parser at `src/psd_tools/psd/linked_layer.py:100` (`read_unicode_string(fp)`). There is no `basename`, no absolute path rejection, and…

Affected: PyPI: psd-tools

# psd-tools: arbitrary file write/read via smart-object path traversal

## Summary

In `psd-tools` (all releases exposing the `SmartObject` API through **v1.17.0**), `SmartObject.save()` writes an embedded smart object to a path taken verbatim from the PSD file. Because that name is attacker-controlled and unsanitised, a tool that extracts embedded objects from an untrusted `.psd` can be made to write attacker-chosen bytes to an attacker-chosen path (absolute or `../`-traversing), outside its intended output directory.

A secondary issue in `SmartObject.open()` for external-kind smart objects allows the attacker-controlled `fullPath` descriptor to be used as an arbitrary file **read** path, enabling exfiltration of the read content to the controlled write destination. Both issues are fixed in **v1.17.1**.

## Details

### Write path — `SmartObject.save()` (primary)

`src/psd_tools/api/smart_object.py:170-179` (tag `v1.17.0`):

```python def save(self, filename: str | None = None) -> None: if filename is None: filename = self.filename # untrusted, straight from the file with open(filename, "wb") as f: f.write(self.data) # attacker-controlled bytes ```

`self.filename` comes from the file with no validation — the `filename` property (`:62-67`) returns `self._data.filename`, set by the linked-layer parser at `src/psd_tools/psd/linked_layer.py:100` (`read_unicode_string(fp)`). There is no `basename`, no absolute path rejection, and…

Affected: Ubuntu:24.04:LTS: psd-tools, Ubuntu:26.04:LTS: psd-tools

psd-tools is a Python package for working with Adobe Photoshop PSD files. Prior to version 1.17.1, `SmartObject.save()` writes an embedded smart object to a path taken verbatim from the PSD file. Because that name is attacker-controlled and unsanitised, a tool that extracts embedded objects from an untrusted `.psd` can be made to write attacker-chosen bytes to an attacker-chosen path (absolute or `../`-traversing), outside its intended output directory. A secondary issue in `SmartObject.open()` for external-kind smart objects allows the attacker-controlled `fullPath` descriptor to be used as an arbitrary file read path, enabling exfiltration of the read content to the controlled write destination. Both issues are fixed in v1.17.1.