fpdf2 implicitly loads external URLs and local image paths when rendering attacker-controlled content

fpdf2 is a PDF creation library for Python. Prior to 2.8.8, fpdf2's shared image loader automatically dereferences attacker-controlled HTTP(S) URLs and raw local paths supplied through FPDF.image(), FPDF.write_html() HTML <img src> values, SVG <image href> or xlink:href values, and template image fields. This can cause outbound requests to attacker-selected internal or external services and local file open attempts, although local content is exposed only when it is a valid supported image or SVG resource. file:// URLs are not specially handled, so the local-path case requires a raw filesystem path. This issue is fixed in version 2.8.8.