GHSA-3vf6-64vr-3g56 is a low-severity (CVSS 3.1) CWE-862 vulnerability in open-webui. A fix is available for open-webui — see the affected versions and patch details below.
Open WebUI: Any authenticated user can cancel another user's chat generation via the chat delete endpoint
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 GHSA-3vf6-64vr-3g56.
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
GHSA-3vf6-64vr-3g56 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 376,715 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
DELETE /api/v1/chats/{id} cancelled a chat's in-flight tasks before it checked whether the caller was allowed to delete that chat. Any authenticated user who knew another user's chat id could therefore abort that user's running model response, title generation or tag generation. The deletion itself was still refused, so the only missing control was on the cancellation side effect.
Preconditions
Default configuration, no special deployment shape. The attacker needs a normal account with the default user role and nothing else: the chat.delete permission is not required, and revoking it does not prevent the cancellation. The attacker also needs the victim's chat id, which is returned by the read-only shared-chat endpoint when a chat or a folder has been shared with them - otherwise enumerating the chat id requires guessing the chat id or brute forcing it, and the victim must have a generation running at that moment.
Impact
A user can repeatedly interrupt another user's generations without any write access to the target chat. Nothing is deleted, modified or disclosed, and the victim can simply regenerate, so the effect is limited to availability of in-flight responses. Because the attacker only needs a chat id, the interruption can be scripted and repeated for as long as the id stays valid.
Fix
Fixed in https://github.com/open-webui/open-webui/pull/27006, released in 0.11.0. The handler now resolves and authorizes the chat first and only cancels tasks and deletes once the caller is an admin or a permitted owner; an unauthorized caller gets 401 or 404 with no cancellation.
Root cause
Affected component: delete_chat_by_id in backend/open_webui/routers/chats.py, serving DELETE /api/v1/chats/{id}. Affected setup: every build from 0.9.6 up to and including 0.10.2.
The cancellation was written as a cleanup step for the delete that follows it, and it was placed at the top of the handler so that it would run before the chat row disappeared. That put an unauthenticated-by-ownership side effect ahead of every check in the function: the admin branch, the chat.delete permission check, and the owner lookup all ran afterwards, so their outcome could no longer affect whether the tasks were stopped. The dedicated task-stop endpoint already verified ownership before calling the same helper, so the intended ordering existed elsewhere in the codebase.
Proof of concept
Against a 0.10.2 instance with two accounts, a victim admin and an attacker holding the default user role, and an upstream that streams slowly:
- As the victim, start a generation in a chat and confirm
GET /api/tasks/chat/{chat_id}reports one active task. - As the attacker, confirm
GET /api/v1/chats/{chat_id}returns 401, then sendDELETE /api/v1/chats/{chat_id}. - The delete is refused with 404, the chat still exists, but the victim's task list is now empty and the assistant message is marked done mid-generation. A control run without step 2 keeps generating.
Repeating step 2 with the chat.delete permission revoked for the user role returns 401 and still cancels the task. The same sequence against 0.11.0 leaves the task running.
Credits
@GabrielGomesAL, who reported the missing authorization on the chat delete endpoint.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | open-webui | ≥ 0.9.6&&< 0.11.0 | 0.11.0pip install --upgrade 'open-webui==0.11.0' |
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 0.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3vf6-64vr-3g56 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 GHSA-3vf6-64vr-3g56 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-3vf6-64vr-3g56. 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-3vf6-64vr-3g56 in your dependencies?
O3 Security finds GHSA-3vf6-64vr-3g56 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.