Cross-origin iframe permission inheritance via XSLT

Cross-origin permission bypass in Mozilla Firefox before 104 allows remote attackers to access parent-origin media permissions via an XSLT iframe. During XSLT transformation, the result document resets FeaturePolicy to a permissive default instead of inheriting the source document policy, allowing a cross-origin child to request or access microphone and camera permissions granted to the top-level origin. Exploitation requires a victim to load attacker-controlled content in the browser; the demonstrated impact is unauthorized media access or permission prompts in the parent origin.