Description
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.6,Open WebUI renders Mermaid blocks from Markdown files in the file preview panel and inserts the generated SVG into the DOM using innerHTML. Because Mermaid is configured with securityLevel: 'loose', attacker-controlled Mermaid content can be rendered unsafely in this flow. A working payload was validated through the Markdown preview path, resulting in JavaScript execution in the victim’s browser under the application origin. This vulnerability is fixed in 0.9.6.
References (1)
Core 1
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/open-webui/open-webui/security/advisories/GHSA-v8qj-hxv7-mgvv
Scores
CVSS v3
8.7
EPSS
0.0020
EPSS Percentile
10.0%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
total
Details
CWE
CWE-79
Status
published
Products (2)
open-webui/open-webui
< 0.9.6
openwebui/open_webui
< 0.9.6
Published
Jun 23, 2026
Tracked Since
Jun 23, 2026