fix: guard knowledge file mutations

[cursor]

Pull Request Checklist

Note to first-time contributors: Please open a discussion post in Discussions and describe your changes before submitting a pull request.

Before submitting, make sure you've checked the following:

• Target branch: Please verify that the pull request targets the dev branch.
• Description: Provide a concise description of the changes made in this pull request.
• Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
• Documentation: Have you updated relevant documentation Open WebUI Docs, or other documentation sources?
• Dependencies: Are there any new dependencies? Have you updated the dependency versions in the documentation?
• Testing: Have you written and run sufficient tests to validate the changes?
• Code review: Have you performed a self-review of your code, addressing any coding standard issues and ensuring adherence to the project's coding standards?
• Prefix: To clearly categorize this pull request, prefix the pull request title using one of the following:
  • BREAKING CHANGE: Significant changes that may affect compatibility
  • build: Changes that affect the build system or external dependencies
  • ci: Changes to our continuous integration processes or workflows
  • chore: Refactor, cleanup, or other non-functional code changes
  • docs: Documentation update or addition
  • feat: Introduces a new feature or enhancement to the codebase
  • fix: Bug fix or error correction
  • i18n: Internationalization or localization changes
  • perf: Performance improvement
  • refactor: Code restructuring for better maintainability, readability, or scalability
  • style: Changes that do not affect the meaning of the code (white space, formatting, missing semi-colons, etc.)
  • test: Adding missing tests or correcting existing tests
  • WIP: Work in progress, a temporary label for incomplete or ongoing work

Changelog Entry

Description

• Bug and impact: A user with write access to any knowledge base could submit another user's guessed file_id to knowledge file routes. Add/batch-add could index foreign file contents into the caller's knowledge base, while remove deleted the global file database record before verifying the file belonged to that knowledge base, causing cross-user data loss.
• Root cause: Knowledge file endpoints authorized the knowledge base but did not authorize the referenced file or verify membership before vector/database mutations. The remove endpoint also treated a knowledge detach as a global file deletion.
• Fix: Require users to own files (or be admin) before adding them to knowledge, require update/remove file IDs to already belong to the target knowledge base before file lookup or vector mutation, and remove the global file deletion from knowledge detach.

Added

• Dependency-light knowledge file helper coverage in tests/test_knowledge_file_regressions.py.

Changed

• Knowledge file add, update, remove, and batch-add routes now enforce file ownership/membership invariants before processing.

Deprecated

• None.

Removed

• Removed unintended global file-row and per-file vector collection deletion from knowledge file detach.

Fixed

• Fixed cross-user knowledge file IDOR/data-loss path in knowledge file mutation endpoints.

Security

• Prevents unauthorized indexing of another user's file content and prevents deleting unrelated file records via /api/v1/knowledge/{id}/file/remove.

Breaking Changes

• None.

---

Additional Information

• Validation performed:
  • python3 -m py_compile backend/open_webui/utils/knowledge_files.py backend/open_webui/routers/knowledge.py tests/test_knowledge_file_regressions.py
  • python3 tests/test_knowledge_file_regressions.py
  • git diff --cached --check

Screenshots or Videos

• Not applicable; backend authorization/data-loss fix.

Contributor License Agreement

By submitting this pull request, I confirm that I have read and fully agree to the Contributor License Agreement (CLA), and I am providing my contributions under its terms.