CVE-2026-56398

Summary

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 Software

Weaknesses

• CWE-20: Improper Input Validation

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://github.com/open-webui/open-webui/security/advisories/GHSA-3wgj-c2hg-vm6q
• https://www.vulncheck.com/advisories/open-webui-stored-cross-site-scripting-via-oauth-picture-claim-svg-data-uri

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