Medium

Open WebUI has unauthorized deletion of knowledge files

  • Disclosed: 27.03.2026
  • Updated: 11.10.2026 14:18

Summary

An access control check is missing when deleting a file from a knowledge base. The only check being done is that the user has write access to the knowledge base (or is admin), but NOT that the file actually belongs to this knowledge base. It is thus possible to delete arbitrary files from arbitrary knowledge bases (as long as one knows the file id)

Details

The source code at https://github.com/open-webui/open-webui/blob/main/backend/open_webui/routers/knowledge.py#L803 does not properly validate that the file being deleted belongs to the current knowledge base:

@router.post("/{id}/file/remove", response_model=Optional[KnowledgeFilesResponse])
def remove_file_from_knowledge_by_id(
    id: str,
    form_data: KnowledgeFileIdForm,
    delete_file: bool = Query(True),
    user=Depends(get_verified_user),
    db: Session = Depends(get_session),
):
    knowledge = Knowledges.get_knowledge_by_id(id=id, db=db)
    [...]
    # Note  : Access control check on the knowledge base
    if (
        knowledge.user_id != user.id
        and not AccessGrants.has_access(
            user_id=user.id,
            resource_type="knowledge",
            resource_id=knowledge.id,
            permission="write",
            db=db,
        )
        and user.role != "admin"
    ):
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=ERROR_MESSAGES.ACCESS_PROHIBITED,
        )

    file = Files.get_file_by_id(form_data.file_id, db=db)
    [...]
    # Note : No checks on the file

    if delete_file:
        try:
            # Remove the file's collection from vector database
            file_collection = f"file-{form_data.file_id}"
            if VECTOR_DB_CLIENT.has_collection(collection_name=file_collection):
                VECTOR_DB_CLIENT.delete_collection(collection_name=file_collection)
        except Exception as e:
            log.debug("This was most likely caused by bypassing embedding processing")
            log.debug(e)
            pass

        # Delete file from database
        Files.delete_file_by_id(form_data.file_id, db=db)
[...]

PoC

Victim has a knowledge base with a file (id: 9db6dcee-bb3b-483e-aaf3-310fda366af1) Attacker creates their own collection (id: dde9e2b6-21c9-4aa1-a1cf-8cb0e4392f2b) Attacker deletes the victim file from their own collection:

POST /api/v1/knowledge/dde9e2b6-21c9-4aa1-a1cf-8cb0e4392f2b/file/remove HTTP/1.1
Host: gaius-neo-val.fr.space.corp
Authorization: Bearer eyJhbGciOiJIUzI1[...]nHiaod-3vfNE0
[...]

{"file_id":"9db6dcee-bb3b-483e-aaf3-310fda366af1"}

-----

HTTP/1.1 200 OK
[...]

The file is then deleted from the victim's knowledge base.

Impact

Arbitrary file deletion

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) open-webui < 0.8.6 0.8.6

References

CVSS score 5.4/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
Weakness (CWE)
CWE-862
Platform
Python (PyPI)
Package
open-webui
Disclosed
27.03.2026
Updated
11.10.2026 14:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-2693 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-26gm-93rw-cchf - CC BY 4.0

Vulnerability history: open-webui

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (161) in the archive
Total entries
161
First → latest
08.2024 09.2026
Without a fix
11
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 77
  • Medium 75
  • Low 8

Disclosures per year

  1. 2024: 3
  2. 2025: 21
  3. 2026: 137
Severity:
  1. Open WebUI has unauthorized deletion of knowledge files this entry
    Medium · 5.4 CVE-2026-29070 < 0.8.6 0.8.6
  2. High · 7.7 CVE-2026-59221 >= 0.9.6, < 0.10.0 0.10.0
  3. High · 7.3 CVE-2026-59214 < 0.10.0 0.10.0
  4. High · 8.7 CVE-2026-54011 < 0.9.6 0.9.6
  5. High · 7.1 CVE-2026-45349 < 0.9.0 0.9.0
Show more (20) Showing 41 of 79

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