CVE-2026-55380

A flaw was found in Pillow, a Python imaging library. A remote attacker could exploit this vulnerability by providing a specially crafted GD 2.x image file. The GdImageFile._open() function reads image dimensions without proper validation, leading to excessive memory allocation. This can result in a Denial of Service (DoS) due to C-heap exhaustion.

A denial-of-service vulnerability was found in Pillow's GdImageFile plugin. The GdImageFile._open() function reads image dimensions from GD 2.x file headers and stores them without performing a decompression bomb check. A crafted .gd file of approximately 1 KB can trigger an unchecked 4.3 GB C-heap allocation, potentially crashing the process or exhausting memory on systems with insufficient resources. This issue is fixed in Pillow 12.3.0.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Avoid processing untrusted GD 2.x image files with PIL.GdImageFile.open(). Use Image.open() instead, which includes decompression bomb protections for supported formats. If GdImageFile must be used, validate the image dimensions before calling load(). Restricting accepted image formats at the application boundary to only those explicitly needed can reduce exposure.