CVE-2026-28788Public exploitNetwork attack vector

Authenticated file overwrite via unchecked batch endpoint

Published Mar 26, 2026 · Updated Mar 26, 2026

Broken object authorization in Open WebUI before 0.8.6 allows remote authenticated users to overwrite shared knowledge-base files. The process_files_batch() route writes attacker-supplied content to file records selected by UUID without checking ownership. Read access to a shared knowledge base reveals the required UUIDs, enabling persistent data corruption and control of content supplied to other users through RAG.

CVSS severity7.1
High
EPSS probability2.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Broken object authorization in Open WebUI before 0.8.6 allows remote authenticated users to overwrite shared knowledge-base files. The process_files_batch() route writes attacker-supplied content to file records selected by UUID without checking ownership. Read access to a shared knowledge base reveals the required UUIDs, enabling persistent data corruption and control of content supplied to other users through RAG.

The record

CVE
CVE-2026-28788
Published
Mar 26, 2026
Updated
Mar 26, 2026
Vendor
Open WebUI
Product
Open WebUI
Classifications
CWE-639, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 26, 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=< 0.8.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Open WebUI · Open WebUIversion=< 0.8.6

Published CVSS scores

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

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-639Authorization Bypass Through User-Controlled Key
T1565.001Data Manipulation: Stored Data Manipulation

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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