What’s Vulnerable › Vulnerabilities

CVE-2026-70483: Open WebUI: Any authenticated user can cancel another user's chat generation via the chat delete endpoint

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-08-04 · updated 2026-09-18
• Weakness: CWE-862

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.

Affected products

• open-webui: from 0.9.6 before 0.11.0 — fixed in 0.11.0

How to fix

Upgrade to a fixed version: open-webui 0.11.0. Check the vendor advisory for mitigations.

References

• https://github.com/open-webui/open-webui/commit/4f93c3e36c1734342a32c312bdb0516c66d8e93c
• https://github.com/open-webui/open-webui/pull/27006
• https://github.com/open-webui/open-webui/releases/tag/v0.11.0
• https://github.com/open-webui/open-webui/security/advisories/GHSA-3vf6-64vr-3g56
• https://github.com/open-webui/open-webui/security/advisories/GHSA-3vf6-64vr-3g56

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