CVE-2026-70483
Received Received - Intake

Unauthorized Task Cancellation in Open WebUI

Publication date: 2026-08-04

Last updated on: 2026-08-04

Assigner: GitHub, Inc.

Description
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.6 until 0.11.0, DELETE /api/v1/chats/{id} cancelled a chat's in-flight tasks before checking whether the caller could delete that chat. Any authenticated user who knew another user's chat id could abort that user's running model response, title generation, or tag generation, even though the delete was refused and no chat data was deleted, modified, or disclosed. This issue is fixed in 0.11.0.

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Meta Information

Published
2026-08-04
Last Modified
2026-08-04
Generated
2026-08-05
AI Q&A
2026-08-04
EPSS Evaluated
N/A
NVD
CVE-2026-70483
EUVD
EUVD-2026-52888

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
open_webui open_webui From 0.9.6 (inc) to 0.11.0 (exc)
open_webui open_webui 0.11.0
open_webui open_webui to 0.11.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

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Executive Summary

This vulnerability in Open WebUI (versions 0.9.6 to 0.11.0) allowed authenticated users to cancel another user's ongoing chat tasks like model responses, title generation, or tag generation by sending a DELETE request to the chat endpoint. The attacker only needed the victim's chat ID, which could be obtained through shared chats or folders. The issue occurred because the system canceled tasks before verifying user permissions.

Detection Guidance

To detect this vulnerability, check Open WebUI versions between 0.9.6 and 0.10.2. Verify if unauthorized users can cancel tasks by sending DELETE requests to /api/v1/chats/{id} with another user's chat ID. Monitor logs for repeated 401/404 responses after task cancellations.

Impact Analysis

An attacker could disrupt your ongoing AI tasks by canceling them prematurely, forcing you to restart the process. While no data is deleted or disclosed, this could waste time and resources, especially if the attack is automated or repeated. The impact is primarily on availability rather than confidentiality or integrity.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar regulations as it does not involve data disclosure, modification, or loss. The impact is limited to service disruption, which may indirectly affect operational availability but does not violate these standards.

Mitigation Strategies

Upgrade Open WebUI to version 0.11.0 or later. Ensure proper authorization checks are enforced before task cancellation. Review logs for suspicious DELETE requests targeting other users' chat IDs.

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