CVE-2026-70486

Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcoding allow-same-origin

MEDIUM
5.4
CVSS Score
Published: August 4, 2026 at 08:01 PM UTC
Updated: September 18, 2026 at 02:59 PM UTC
1 product affected across 1 vendorOpen Webui

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.0 until 0.11.0, the terminal file-preview serveUrl iframe branch always granted allow-same-origin together with allow-scripts for HTML files served from the application origin. Any authenticated user with access to a configured terminal server could cause script in a previewed file to run in the Open WebUI origin, read the victim's session token from localStorage, and take over the account, with possible server-side code execution if the victim was an admin or held workspace.functions. This issue is fixed in 0.11.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.11.00.9.0 ≤ v < 0.11.0
Affected range stops below 0.11.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMExploitPatchVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/security/advisories/GHSA-3xpf-xq7r-v8c5
x_refsource_MISCPatchVendor Advisory
Source: cverecord
https://github.com/open-webui/open-webui/pull/26907
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/open-webui/open-webui/releases/tag/v0.11.0

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-79CWE-1021

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