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Open WebUI: Sharing models for others to use (read permission) also exposes model details (system prompt leakage)

Moderate severity GitHub Reviewed Published May 10, 2026 in open-webui/open-webui • Updated May 15, 2026

Package

pip open-webui (pip)

Affected versions

<= 0.9.4

Patched versions

0.9.5

Description

Summary

When setting model permissions so that a group has read access to it, intending for other users to use it, those users also can read the model's system prompt.

However users may consider their system prompt confidential, so we consider this a security issue.

Compare https://genai.owasp.org/llmrisk/llm072025-system-prompt-leakage/ or prompt injections to get popular chatbots on the internet to reveal their prompt.

Details

We discovered that users can open the workspace model edit page /workspace/models/edit?id=notmymodel for models that do not appear in their workspace.

Saving is not possible, that permission check is correct.

On the API level:

  • /api/v1/models/model?id=notmymodel -> returns the model details, most importantly params.system
  • even though /api/v1/models/list does NOT contain the model since it checks for write permission.
  • /api/models contains the model correctly and does not reveal the system prompt.

It seems inconsistent that the REST API list does not contain an item, but if you know the id, you can access it anyway.

PoC

  • create model
  • give read permission to group with another user
  • other user can access /api/v1/models/model?id=notmymodel

Impact

System prommpt leakage

If this is intended behavior for the "read" permission, maybe there should be an additional "use" permission (which would be 99% of use cases of the read permission i believe).

References

@doge-woof doge-woof published to open-webui/open-webui May 10, 2026
Published to the GitHub Advisory Database May 14, 2026
Reviewed May 14, 2026
Published by the National Vulnerability Database May 15, 2026
Last updated May 15, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(8th percentile)

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

CVE ID

CVE-2026-45387

GHSA ID

GHSA-h2cw-7qw9-56xr

Source code

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