Xiaozhi-esp32-server-java versions up to 6.1.0 suffer an authentication bypass that lets an unauthenticated attacker retrieve a valid WebSocket token by submitting a request to the /api/device/ota endpoint with any MAC address. This flaw is a CWE-290 Authentication Bypass vulnerability. The token permits the attacker to open the device’s WebSocket channel, read confidential role prompts, inject or modify conversation history, consume credentials for large‑language‑model, speech‑to‑text, and text‑to‑speech services, and overwrite device metadata. This flaw enables unauthorized information disclosure and manipulation of device state but does not provide arbitrary code execution or system‑wide compromise.

The vendor is Joey‑zhou’s Xiaozhi‑esp32‑server‑java, a lightweight Java framework for ESP32 devices. Versions 6.1.0 and earlier are vulnerable. No other products or vendors are listed on the CNA record.

The calculated CVSS score of 6.3 indicates a moderate severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog. The likely attack vector is inferred to require network reach to the target device, typically on the local or exposed network, to send requests to the OTA endpoint and harvest a token. Once the token is acquired, the attacker can exercise powerful read/write capabilities over WebSocket, but the flaw does not grant arbitrary code execution. The risk is therefore moderate but immediate remediation is advised.