GHSA-cx9v-4qj2-jrw6: Open WebUI BOLA: `search_knowledge_files` Allows Unauthorized Knowledge Base File Enumeration
SummaryOpen WebUI has a Broken Object Level Authorization (BOLA) vulnerability in the builtin `search_knowledge_files` tool.When native function calling is enabled and the selected model has no attached knowledge bases, an authenticated user can call `search_knowledge_files` with an arbitrary `knowledge_id`. The function then returns file metadata from that knowledge base without checking whether the user has read access.This allows unauthorized enumeration of private or restricted knowledge base files.DetailsThe vulnerable code is in:`backend/open_webui/tools/builtin.py`Affected function:In the "No attached knowledge" branch, when `knowledge_id` is provided, the function directly calls:This code path does not verify that the current user is authorized to access the specified knowledge base.The missing check is inconsistent with other nearby code paths. For example, the attached-knowledge branch in the same function checks whether the user is an admin, the owner of the knowledge base, or has explicit read access through `AccessGrants`:The sibling function `query_knowledge_files` also performs the same authorization check before using user-supplied knowledge base IDs.The underlying method `Knowledges.search_files_by_id()` receives `user_id`, but it does not enforce authorization for the provided `knowledge_id`. As a result, this builtin tool path can access a knowledge base by ID without verifying the caller's permissions.PoCPrerequisitesThe attacker has a valid authenticated Open WebUI account.The victim owns a private or restricted knowledge base.The attacker does not own the target knowledge base.The attacker does not have `read` permission for the target knowledge base in `AccessGrants`.The attacker knows the target `knowledge_id`.The selected model has no attached knowledge bases.Builtin tools are enabled.The knowledge builtin tool category is enabled.Native function calling is enabled.Reproduction StepsCreate a private or restricted knowledge base as the victim user.Upload one or more files to that knowledge base.Confirm that the attacker user does not have access to the knowledge base.As the attacker user, send a chat completion request with native function calling enabled:Replace `c0c84752-2e9d-42bf-bc3c-c0f272aa61c1` with the victim's private knowledge base ID.Expected ResultThe request should be denied because the attacker does not have access to the target knowledge base.Actual Result`search_knowledge_files` returns metadata for files inside the target knowledge base, including:file ID;filename;knowledge base ID;knowledge base name;update timestamp.ImpactThis is a Broken Object Level Authorization / Broken Access Control vulnerability.An authenticated attacker who knows a valid `knowledge_id` can enumerate files from private or restricted knowledge bases without authorization.The leaked metadata may expose sensitive information through filenames, such as:financial reports;employee documents;customer contracts;internal roadmap files;confidential project documents.The exposed file IDs may also help attackers chain this issue with other knowledge-file access paths, such as `view_knowledge_file`, to attempt further content extraction.This vulnerability bypasses the intended `AccessGrants` permission model and may also allow post-revocation metadata access if a user remembers a previously accessible `knowledge_id`.Suggested FixAdd the same authorization check used in `query_knowledge_files` before calling `Knowledges.search_files_by_id()`:As defense in depth, authorization should also be enforced or safely wrapped around `Knowledges.search_files_by_id()` so that future callers cannot accidentally bypass access control.
CVSS v3.1: 4.3