Audiobookshelf is a self-hosted audiobook and podcast server. A stored cross-site scripting (XSS) vulnerability exists in versions prior to 0.12.0-beta of the Audiobookshelf mobile application that allows arbitrary JavaScript execution through malicious library metadata. Attackers with library modification privileges can execute code in victim users' browsers/WebViews, potentially leading to session hijacking, data exfiltration, and unauthorized access to native device APIs. The issue is fixed in audiobookshelf-app version 0.12.0-beta, corresponding to audiobookshelf version 2.12.0.