Banana Slides through version 0.4.0 contains a path traversal vulnerability in the generate_image() function within the AI service backend. The vulnerability allows unauthenticated attackers to read arbitrary image-format files outside the intended uploads directory by exploiting an incomplete path prefix check using os.path.startswith() without a trailing separator. Attackers can supply crafted markdown image references in user-controlled page descriptions that resolve to sibling directories whose names share the uploads folder prefix. This bypasses the directory confinement check and causes the application to read files from unintended locations via PIL Image.open(). The issue was patched in commit e8bc490.