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

> Attackers can execute scripts via malicious SVG profile images in Open WebUI, stealing tokens and taking over accounts.

- **Severity:** High 8.5 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 15 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-3wgj-c2hg-vm6q, GHSA-5p6h-xfw9-p64q

## What is CVE-2026-56398?

CVE-2026-56398 is a high-severity cross-site scripting vulnerability in Openwebui Open Webui, published on 15 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### 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.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-56398?

2 open source packages ship an affected version, including open-webui. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `open-webui` | PyPI | All versions | 0.9.5 |
| `open-webui` | PyPI | All versions | 0.9.5 |

Products: Openwebui Open Webui.

## How do I fix CVE-2026-56398?

Upgrade open-webui to 0.9.5 or later.

## Is CVE-2026-56398 being exploited?

There is no known exploitation of CVE-2026-56398 in the wild and no public exploit code.

## Other vulnerabilities in Openwebui Open Webui

- [CVE-2026-44551](https://insights.sbomify.com/CVE-2026-44551/): Open WebUI: LDAP Empty Password Authentication Bypass (critical 9.1)
- [CVE-2026-56400](https://insights.sbomify.com/CVE-2026-56400/): open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation (critical 9.0)
- [CVE-2024-8017](https://insights.sbomify.com/CVE-2024-8017/): Cross-site Scripting (XSS) in open-webui/open-webui (critical 9.0)
- [CVE-2026-45672](https://insights.sbomify.com/CVE-2026-45672/): Open WebUI: Jupyter code execution works despite `ENABLE_CODE_EXECUTION=false` — feature gate bypassed (high 8.8)
- [CVE-2026-87995](https://insights.sbomify.com/CVE-2026-87995/): Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56398 and fix it if it is affected.

What it is: CVE-2026-56398 is a high-severity cross-site scripting vulnerability in Openwebui Open Webui, published on 15 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-56398 in the wild and no public exploit code.

Affected packages and fixed versions:
- open-webui (PyPI): affected all versions; fixed in 0.9.5
- open-webui (PyPI): affected all versions; fixed in 0.9.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-56398/ (Markdown: https://insights.sbomify.com/CVE-2026-56398/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56398
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56398
- OSV: https://osv.dev/vulnerability/CVE-2026-56398

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56398/
Summaries are generated and may contain mistakes; the official description above is the record.