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vulnerability / NVI-00017838 / Revision 1

Open WebUI: Any authenticated user can hang the server via message deletion in a cyclic chat tree

GitHub lists this reviewed advisory for open-webui. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.

source listedactiveGHSA-3cgp-3cqx-j8w2CVE-2026-88000

This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.

01 / Meaning

Why it matters

Published affected context helps an owner decide what evidence to gather. This report has not examined your application.

CVSS

6.5 medium

GitHub source severity; exploitability and local consequence require separate evidence.

As of · GitHub Advisory Database

02 / Applicability

The affected context

Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.

open-webui

source listed
  • >= 0.10.0, < 0.11.1

## Summary Chat histories are stored as an unvalidated JSON object. After a message is deleted, the code that picks the chat's new current message walked down the `childrenIds` links without recording where it had already been. Any account with the default `user` role could store a chat whose messages list each other as children, then delete a message from it, and the walk would run forever. That walk runs on the server's request loop, so it blocks every other user's requests until the process is killed. ## Preconditions One account with the default `user` role. No administrator rights, no additional permissions, no configuration change and no non-default setting: creating and deleting chats is available to every user out of the box. The attack runs entirely against the attacker's own chat, so no knowledge of any other user's data is needed. Versions before 0.10.0 are unaffected because neither the message-deletion endpoint nor the affected code existed. ## Impact The walk is synchronous and runs on the asyncio event loop, so while it spins, every request from every user is blocked, including unauthenticated `/health` and administrator endpoints. External health checks and orches

GitHub Advisory Database

03 / Response

What to do next

  1. investigate

    Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.

    Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database

A fixed release is not deployment evidence.

Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.

04 / Limits

What this report cannot establish

  • Customer inventory, deployment, reachability and exploitation have not been inspected.
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05 / Provenance

Sources you can inspect

Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.

  1. GHSA-3cgp-3cqx-j8w2 ↗

    GitHub Advisory Database · vendor advisory

    Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.

Public revision history

Only published revisions appear here. Routine fetches do not create a material-change event.

  1. Revision 1 ·

    First indexed by Null; source disclosure date is shown separately.

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The next step is private

Bring the question into your environment.

The connected workflow is a development preview for inventory, contextual matching, owner decisions and evidence-based verification. No system-specific result is generated by this page.

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