CVE-2026-56398CWE-20

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

High · published July 15, 2026

CVSS v4.0
8.5
EPSS
1%
Percentile
49.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.5 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00635 · 49.8th percentile
Weakness
CWE-20 · Improper Input Validation
Published
2026-07-15T11:25Z
EPSS history
Timeline
  • 15 JUL 11:25Z
    Open WebUI - Stored Cross-Site Scripting via OAuth Picture Claim SVG Data URI
    cvelistv5