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Open WebuiApplication · Openwebui

CVE-2026-56398

CRITICAL · 9.0 CVSS v3.1 Published 2026-07-15
Fix available
A fix is available. Upgrade to 0.9.5 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Open WebUI before 0.9.5 has a stored XSS vulnerability in the OAuth authentication flow where the profile picture claim URL's MIME type is inferred from the file extension rather than the Content-Type header. This allows attackers to bypass the image validator using .svg files, which get stored as data URIs. When users view the profile image endpoint, the attacker-controlled SVG content executes in the same origin, enabling theft of authentication tokens and account takeover.

MitigationUpgrade to Open WebUI 0.9.5 or later. The fix should validate MIME type from the actual Content-Type header, reject or sanitize SVG files, and apply security headers (Content-Disposition, CSP) to the profile image endpoint.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Open WebuiApplication
Affected:< 0.9.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Open WebUI version
    Locate the version file or check the Docker image tag. Common paths: check the UI footer version number, or inspect the running container/image for version metadata. Compare against < 0.9.5
    Affected if Version is before 0.9.5
  2. Verify OAuth authentication is configured
    Check the Open WebUI configuration files or environment for OAuth provider settings (OIDC, Google, GitHub, etc.). Look for flags like OIDC_URL, OAUTH_PROVIDERS, or similar OAuth-related environment variables.
    Affected if OAuth providers are configured and enabled
  3. Confirm profile picture import from OAuth is allowed
    Inspect whether the OAuth configuration allows importing user profile pictures. Check if 'picture' or 'avatar' claims from the OAuth provider are being processed and stored.
    Affected if OAuth profile picture import is enabled and the 'picture' claim is processed
  4. Test if SVG files can be uploaded as profile picture URL
    During OAuth login, if a custom profile picture URL can be provided or if the OAuth provider returns an SVG URL, verify how the system handles it. Check if the MIME type validation only looks at file extension rather than Content-Type header.
    Affected if SVG URLs in the picture claim are accepted without proper sanitization or MIME type validation from Content-Type header

A user is affected if they run Open WebUI version < 0.9.5 with OAuth authentication configured and profile picture import enabled, allowing SVG files to be stored as profile images.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.9.5 or later
Fixed in 0.9.5
Interim mitigation

Upgrade to Open WebUI 0.9.5 or later. The fix should validate MIME type from the actual Content-Type header, reject or sanitize SVG files, and apply security headers (Content-Disposition, CSP) to the profile image endpoint.

Recommended fix High confidence

Open WebUI 0.9.5

  1. 1. Backup your Open WebUI installation and any user data before upgrading.
  2. 2. Upgrade Open WebUI to version 0.9.5 or later by following your deployment method (e.g., Docker pull, pip install, or package manager).
  3. 3. Verify the upgrade completed successfully by checking the version number in the admin interface or via command line.
  4. 4. After upgrading, test the OAuth profile image upload flow to confirm SVG files are now properly rejected based on Content-Type header validation rather than file extension.
Caveat Review the 0.9.5 release notes for any breaking changes; the description does not indicate major breaking changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Open Webui Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,670
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-56398 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data