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.
{
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-20"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56398.json"
}{
"cpe": "cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "0.9.5"
}
],
"source": [
"AFFECTED_FIELD",
"CPE_RANGE"
]
}