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Medium, CVSS 6.5amended

Open WebUI: Any authenticated user can hang the server via a cyclic chat message history

CVE-2026-88002GHSA-jqhh-cjmq-vmv6

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (open-webui 0.11.1), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • PyPI open-webui

    Affected
    >= 0.5.0, < 0.11.1
    Fixed in
    0.11.1

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-88002: 0.58% estimated exploitation activity in the next 30 days; percentile 47.91 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary Chat histories are stored as an unvalidated JSON object. The walk that reconstructs a chat's message chain detected repeats using each message's own id field while moving through the history by map key, so a message that simply omitted id was never recorded as visited. A history whose messages referenced each other in a parent cycle therefore made the walk run forever. Any account with the default user role could store such a chat and trigger the walk, blocking the server for everyone. Preconditions One account with the default user role. No administrator rights, no additional permissions, no configuration change and no non-default setting: creating a chat 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. Instances where every account is trusted are affected in the sense that the fault is reachable, but require a user acting deliberately. Impact The walk is synchronous and…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-jqhh-cjmq-vmv6

  2. Revision 2 · amended ·

    Amended from osv record GHSA-jqhh-cjmq-vmv6

  3. Revision 1 · created ·

    Published from ghsa record GHSA-jqhh-cjmq-vmv6

Agent brief

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# Patch Next advisory brief: CVE-2026-88002

Advisory: Open WebUI: Any authenticated user can hang the server via a cyclic chat message history
IDs: CVE-2026-88002, GHSA-jqhh-cjmq-vmv6
Record: https://patchnext.com/advisories/cve-2026-88002 (revision 3, source checked 26 Oct 2026, 13:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: open-webui 0.11.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI open-webui: affected >= 0.5.0, < 0.11.1; fixed in 0.11.1

## Suggested inspection (read-only)
- `python -m pip show open-webui`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on open-webui.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jqhh-cjmq-vmv6 (GitHub-reviewed advisory GHSA-jqhh-cjmq-vmv6 lists affected ranges: PyPI open-webui >=0.5.0 <0.11.1)
- Verified: https://osv.dev/vulnerability/GHSA-jqhh-cjmq-vmv6 (OSV record GHSA-jqhh-cjmq-vmv6 lists affected ranges: PyPI open-webui >=0.5.0 <0.11.1 (fixed))

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