Lumiverse versions before 0.9.7 contain a protection mechanism failure (CWE-693) in the component override system. User-supplied TSX is transpiled and evaluated with new Function, with dangerous globals shadowed and blocked by a static validator. Both controls are bypassed: the static validator can be evaded by reconstructing blocked identifiers from string fragments, and the sandbox escape is achieved by using React hooks (useRef, useEffect) to obtain a live DOM node, then accessing the real window object through the node's ownerDocument.defaultView property. Malicious theme packs (.lumitheme/.lumiverse-theme) serve as the attack vector, requiring user interaction to import and enable the override. The vulnerability allows code execution in the victim's authenticated session. The issue is resolved in Lumiverse 0.9.7.

Successful exploitation allows an attacker to execute arbitrary code within the context of an authenticated user session, leading to complete compromise of confidentiality and integrity of user data. The vulnerability does not impact availability. The CVSS 3.1 score is 9.3 (critical), reflecting network attack vector, low attack complexity, no privileges required, user interaction needed, scope change, and high confidentiality and integrity impact.

This vulnerability is fixed in Lumiverse version 0.9.7. Users and administrators should upgrade to version 0.9.7 or later to remediate this issue. There is no official vendor advisory provided here, but the description explicitly states the fix is in 0.9.7. Until upgrading, users should avoid importing or enabling untrusted theme packs or component overrides.