Executive brief
Lumiverse, an AI chat application, contains a security flaw in how it handles custom theme packs. An attacker can create a malicious theme file that, when imported and enabled by a user, executes unauthorized code within the user's active session. This could allow an attacker to perform actions on the user's behalf, access private chat data, or potentially gain further control over the server.
Technical details
The Lumiverse component override system attempts to sandbox user-supplied TSX by transpiling it via Sucrase and evaluating it with 'new Function' while shadowing dangerous globals (like window and fetch) with undefined. It also employs a static source validator (validateComponentOverrideSource) to block forbidden identifiers using regex. These controls are bypassed using two methods: first, string concatenation (e.g., 'ownerDoc' + 'ument') evades the static regex validator; second, by using 'useRef' and 'useEffect' hooks, an attacker can obtain a live DOM node and traverse to the real 'window' object via 'node.ownerDoc.defaultView'. This allows the attacker to bypass all shadowed globals and execute arbitrary code in the context of the victim's authenticated session. The vulnerability is fixed in version 0.9.7.
Affected products
- prolix-oc Lumiverse < 0.9.7
Timeline
- 2026-05-06: advisory: GitHub Security Advisory published by vendor
- 2026-05-26: disclosed: CVE published to NVD
- 2026-05-26: patched: Fix confirmed in version 0.9.7