CVE-2026-56398 Details
Description
Open WebUI before 0.9.5 contains a stored cross-site scripting vulnerability in the OAuth authentication flow where the picture claim URL MIME type is inferred from file extension rather than Content-Type header, allowing SVG files to bypass the profile image validator and be stored as data URIs. Authenticated users who visit the profile image endpoint receive attacker-controlled SVG content with inline disposition and no default security headers, enabling script execution in the same origin to steal authentication tokens and achieve account takeover.
A stored cross-site scripting vulnerability has been identified in Open WebUI versions prior to 0.9.5. The issue arises in the OAuth authentication process, where the MIME type of the picture claim URL is incorrectly inferred from the file extension instead of the Content-Type header. This flaw allows SVG files to bypass the profile image validation and be saved as data URIs. When authenticated users access the profile image endpoint, they receive SVG content controlled by the attacker, which can execute scripts in the same origin, steal authentication tokens, and lead to account takeover.
Users can update to Open WebUI version 0.9.5 or later, where this vulnerability has been patched.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 15, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/open-webui/open-webui/security/advisories/GHSA-3wgj-c2hg-vm6q | [email protected] | ExploitVendor Advisory |
| https://www.vulncheck.com/advisories/open-webui-stored-cross-site-scripting-via-oauth-picture-claim-svg-data-uri | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| openwebui open webui | < 0.9.5 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 16, 2026 | Initial Analysis | [email protected] |
| Jul 15, 2026 | CVE Modified | CISA-ADP |
| Jul 15, 2026 | New CVE Received | [email protected] |