Affected: psd-tools

psd-tools is a Python package for working with Adobe Photoshop PSD files. Prior to 1.17.4, PSDImage.composite() and PSDImage.numpy() allocated output buffers from attacker-controlled PSD header geometry, including width, height, channels, depth, and per-layer rectangles, before validating those values against the available file data. A tiny crafted PSD could therefore cause multi-gigabyte memory allocation, and PSDImage.composite() could return a black image with only a warning instead of raising an exception. Services that composite untrusted PSD files could be terminated by out-of-memory handling. This issue is fixed in version 1.17.4.

Affected: PyPI: psd-tools

### Summary `PSDImage.composite()` (and `.numpy()`) allocate the output image buffer from the PSD's header geometry (width × height × channels × depth, and per-layer rectangles) before validating those values against the actual file contents. A tiny crafted PSD declaring huge dimensions causes a multi-gigabyte allocation. Critically, `composite()` then returns a (black) image with only a warning, no exception is raised, so a caller cannot detect or guard against it.

### Impact On psd-tools 1.17.2 (latest), default usage, a 49-byte PSD makes `composite()` commit ~3 GB and return successfully (warning only); `.numpy()` reaches ~7.5 GB, and the per-layer rectangle is a second lever (up to ~32 GB), all from an input under 100 bytes (input-to-commit amplification over 1000×). Because the buffer is committed before validation and no exception is thrown, any service that composites untrusted PSDs is exposed to denial of service: on a host with less RAM than the attacker-declared geometry the allocation is an unrecoverable OOM-kill.

### Steps to reproduce ```python # pip install psd-tools==1.17.2 from psd_tools import PSDImage psd = PSDImage.open("psd-psdtools-grammar-d23.psd") psd.composite() # commits ~3 GB from a 49-byte file and returns (warning only) ```

PoC (49 bytes), reconstruct with: ```sh base64 -d > psd-psdtools-grammar-d23.psd <<'EOF' OEJQUwABAAAAAAAAAAYAACg4AAAXTAAIAAMAAAAAAAAAAAAAAAAAAUNIUIFU+yQtDw== EOF ``` Verify: ``` 7d8ebf03a54393cb0359ecf4b676d1b08c9a8c6afdd…