Pillow Out-of-Bounds Write Vulnerability in PSD Image Processing

A vulnerability allowing an out-of-bounds write has been identified in the Pillow library, a popular Python imaging library. This issue arises when the library processes specially crafted PSD (Photoshop Document) images. The vulnerability affects versions of Pillow from 10.3.0 up to, but not including, 12.1.1. The out-of-bounds write can potentially lead to memory corruption or other unintended behavior in the application using Pillow.

Impact

Exploitation of this vulnerability can cause an out-of-bounds write, which may lead to memory corruption or other unintended consequences in the application.

Reproduction

The vulnerability can be reproduced by opening a specially crafted PSD file with Pillow versions 10.3.0 to prior to 12.1.1. This can be done using the Image.open() function from the Pillow library, without specifying the 'formats' parameter to exclude PSD files.

Remediation

Users can upgrade to Pillow version 12.1.1, which includes the necessary fix. For those unable to upgrade, the 'formats' parameter in the Image.open() function can be used to prevent PSD images from being opened.