A flaw in the folder deletion API lets a user with write access to a shared folder permanently delete chats and messages belonging to the folder owner. The vulnerability arises because the system authorizes deletion based on the folder’s write grant rather than requiring ownership or administrator rights, allowing a collaborator to cascade the delete operation to the owner’s entire subtree. This leads to irreversible data loss for the owner and can disrupt continuity of work or conversation history.

The issue exists in Open WebUI, specifically in the DELETE /api/v1/folders/{id} handler of the backend code. All releases from version 0.10.0 up to, but excluding, 0.11.0 are affected. The vendor product is Open WebUI, a self‑hosted AI platform.

The vulnerability carries a CVSS score of 8.1, indicating high severity. The EPSS score is not available, so the current probability of exploitation cannot be quantified but the known usage scenario—any user with delegated write permission—makes the risk tangible. The vulnerability is not listed in CISA’s KEV catalog. The likely attack vector involves authenticated HTTP DELETE requests directed at the folder API; a collaborator with write privileges can trigger the deletion without additional authorization.