CVE-2026-45387: Open WebUI: Sharing models for others to use (read permission) also exposes model details (system prompt leakage)

Analyzed

AliasesGHSA-h2cw-7qw9-56xrPYSEC-2026-2728

Published 15-05-2026Last modified 15-05-2026

Vulnerability summary

CVE-2026-45387 is a medium (CVSS 4.3) vulnerability in open-webui. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 22.7% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk

27/100

0100

Medium · default modelHow is this calculated?

CVSS score

4.3/10

010

Medium · v3.1 (CVE.org)

EPSS score

0.31%

0%100%

Low · +0.09 pp in 30 days

KEVNot listedNot listed by any tracked catalog.

RansomwareNot flaggedNo ransomware use recorded.

Public exploits1github

Timeline

15-05-2026
PublishedVulnerability first disclosed.
15-05-2026
Last modifiedVulnerability information updated.

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.5, 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 this is considered a security issue. This vulnerability is fixed in 0.9.5.