Open WebUI versions prior to 0.6.44 are vulnerable to a stored cross-site scripting (XSS) issue via user-controlled iFrame embeds in response messages. The vulnerability arises because the application allows manual modification of chat history to set the embeds property, which is rendered inside an iFrames with a sandbox that improperly enables allow-scripts and allow-same-origin, effectively disabling sandbox protections. This flaw enables attackers to create weaponized chats that execute arbitrary JavaScript in the context of other users' sessions, potentially leading to session token theft and further exploitation. The vulnerability also affects shared chat links, allowing distribution of malicious payloads to other users. No official patch or fix is currently documented in the advisory.