PYSEC-2026-4299 Scrapy: Arbitrary Module Import via Referrer-Policy Header in RefererMiddleware

Impact Since version 1.4.0, Scrapy respects the Referrer-Policy response header to decide whether and how to set a Referer header on follow-up requests. If the header value looked like a valid Python import path, Scrapy would import the referenced object and call it, assuming it referred to a...