Vulnerability · Published Jul 15, 2026 · Assigned by VulnCheck

CVE-2026-56398Open WebUI - Stored Cross-Site Scripting via OAuth Picture Claim SVG Data URI

High 7.3

In plain English

A high-severity improper input validation in open-webui from open-webui. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 51% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High

Exploit odds (30 days)0.6%top 49.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.9.5	GHSA-3wgj-c2hg-vm6q

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	0 – before 0.9.5

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

References

GitHub Security Advisory (GHSA-3wgj-c2hg-vm6q) vendor-advisory
VulnCheck Advisory: Open WebUI - Stored Cross-Site Scripting via OAuth Picture Claim SVG Data URI third-party-advisory