---
cve: "CVE-2026-87995"
severity: "HIGH"
cvss: 8.7
epss: "0.4%"
vendor: "open-webui"
kev: false
exploited: false
published: "2026-09-09 21:26:30"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-11-09T11:32:46+01:00"
---

# CVE-2026-87995

> 8.7 HIGH · 🧪 PoC

## Beschreibung

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.8.11 until 0.11.1, src/lib/components/chat/FileNav/PortPreview.svelte rendered terminal port content in an iframe sandbox containing both allow-scripts and allow-same-origin. Because the terminal proxy serves that content from the Open WebUI origin, an authenticated user with access to a shared terminal server could host script on a previewed port and take over a victim's account when the victim opened the preview. This issue is fixed in version 0.11.1.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-09-10 17:54:56
- CNA-CVSS: **8.7** (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Erforderlich | good |
| S Scope | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Schwachstellen-Klasse

- **CWE-1021** — Improper Restriction of Rendered UI Layers or Frames
  The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain.
- **CWE-79** — Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)
  The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

## Angriffsmuster (CAPEC)

- [CAPEC-103 — Clickjacking](https://capec.mitre.org/data/definitions/103.html) _(Severity: High)_
- [CAPEC-181 — Flash File Overlay](https://capec.mitre.org/data/definitions/181.html) _(Severity: Medium)_
- [CAPEC-222 — iFrame Overlay](https://capec.mitre.org/data/definitions/222.html) _(Severity: High)_
- [CAPEC-504 — Task Impersonation](https://capec.mitre.org/data/definitions/504.html) _(Severity: High)_
- [CAPEC-506 — Tapjacking](https://capec.mitre.org/data/definitions/506.html) _(Severity: Low)_
- [CAPEC-587 — Cross Frame Scripting (XFS)](https://capec.mitre.org/data/definitions/587.html) _(Severity: High)_
- [CAPEC-654 — Credential Prompt Impersonation](https://capec.mitre.org/data/definitions/654.html) _(Severity: High)_

## ATT&CK-Techniken

- [T1036.004 — Masquerading: Masquerade Task or Service](https://attack.mitre.org/techniques/T1036/004/)
- [T1056 — Input Capture](https://attack.mitre.org/techniques/T1056/)
- [T1548.004 — Abuse Elevation Control Mechanism: Elevated Execution with P](https://attack.mitre.org/techniques/T1548/004/)

## Patch verfügbar (OSV)

- d3e8bf3405e848cfba377814d0aa7ba7290e414d (Commit)
- 54d7a223707f03172efbb9e754db6e69709956d0 (Commit)

## Referenzen

- <https://github.com/open-webui/open-webui/security/advisories/GHSA-jmc6-2wr8-h3wj>
- <https://github.com/open-webui/open-webui/commit/54d7a223707f03172efbb9e754db6e69709956d0>
- <https://github.com/open-webui/open-webui/releases/tag/v0.11.1>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-87995/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_