CVE-2026-29070 — open-webui
MEDIUMCVE-2026-29070 is a medium-severity (CVSS 5.4) CWE-862 vulnerability in open-webui. A fix is available for open-webui — see the affected versions and patch details below.
Open WebUI has unauthorized deletion of knowledge files
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-29070.
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.
How urgent is this, really
CVE-2026-29070 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 | 0.8.6pip install --upgrade 'open-webui==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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update open-webui to 0.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-29070 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-29070 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-29070. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-29070 in your dependencies?
O3 Security finds CVE-2026-29070 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.