Astro: Image endpoint in @astrojs/node can read files from a case-variant sibling of the output directory on case-sensitive filesystems

Astro is a web framework for content-driven websites. From 5.14.3 until 7.4.7, Astro's /_image endpoint compared the requested local-image path with the build output directory without preserving case on case-sensitive filesystems. A sibling directory whose path differed from the output directory only by letter case could therefore pass the containment check, allowing an unauthenticated requester to read image files accepted by the image service from outside the output directory. Exploitation required on-demand rendering with the @astrojs/node adapter, a case-sensitive filesystem, and a preexisting case-variant sibling directory; ordinary traversal to unrelated paths was already rejected. This issue is fixed in Astro version 7.4.7.