An unsanitized filename field in the speech‑to‑text transcription endpoint causes a FileNotFoundError to be thrown. The error message contains the server’s absolute DATA_DIR path, which is returned verbatim in the 400 response. This flaw stems from improper input validation and error handling and aligns with CWE‑209 (Information Exposure Through Error Message) and CWE‑22 (Path Traversal).

Open WebUI installations running any version earlier than 0.8.6 are vulnerable to this defect. The issue was resolved in version 0.8.6; all releases equal to or newer than that are considered safe.

The CVSS score of 4.3 reflects moderate severity, and the vulnerability is not listed in the CISA KEV catalog. Exploitation requires authentication as a non‑admin user and allows an attacker to gain the absolute file path of the server, potentially aiding further reconnaissance or targeted attacks. Because the EPSS score is unavailable, the likelihood of exploitation is uncertain, yet the disclosure can be valuable for adversaries.