`IndexError` in `_get_imagemode` on Empty ColorSpace Array

[tylzh97]

Summary

The _get_imagemode function directly indexes the first element of the /ColorSpace array without checking if the array is empty. When processing a crafted XObject with an empty colorspace (colorspace_empty.pdf), this triggers an IndexError and aborts the entire page parsing.

Reproduction

from pypdf import PdfReader

reader = PdfReader(open("poc.pdf", "rb"))
page = reader.pages[0]
page.images[0]

Traceback

Traceback (most recent call last):
  ...
  File "pypdf/_xobj_image_helpers.py", line 67, in _get_imagemode
    elif color_space[0].startswith("/Cal"):  # /CalRGB and /CalGray
IndexError: list index out of range

Suggested Fix

• Check if the list is empty before accessing color_space[0]

poc.zip

[stefan6419846]

Standalone test file: poc.pdf