CVE-2026-45399Public exploitNetwork attack vector

Cross-user task cancellation via missing ownership checks

Published May 15, 2026 · Updated May 15, 2026

Missing authorization in Open WebUI task endpoints before 0.9.0 allows remote authenticated users to cancel other users' tasks. GET /api/tasks exposes the global task namespace, while POST /api/tasks/stop/{task_id} passes raw task IDs to stop_task without checking ownership. Any verified non-admin account in a multi-user deployment can repeatedly interrupt chat generation and other active background work.

CVSS severity7.1
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Open WebUI task endpoints before 0.9.0 allows remote authenticated users to cancel other users' tasks. GET /api/tasks exposes the global task namespace, while POST /api/tasks/stop/{task_id} passes raw task IDs to stop_task without checking ownership. Any verified non-admin account in a multi-user deployment can repeatedly interrupt chat generation and other active background work.

The record

CVE
CVE-2026-45399
Published
May 15, 2026
Updated
May 15, 2026
Vendor
Open WebUI
Product
Open WebUI
Classifications
CWE-862, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 15, 2026CVE publishedPublication date reported by the CVE source.
  2. May 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Open WebUI · Open WebUIversion=< 0.9.0

Published CVSS scores

7.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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