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Fencer Vulns
high 8.2

CVE-2026-70486 json

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

published 2026-08-04 3 mo ago modified 2026-09-18 51 d ago also GHSA-3xpf-xq7r-v8c5 , PYSEC-2026-3641 , EUVD-2026-52893

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi open-webui 0.11.0
  • openwebui open_webui 0.11.0

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/open-webui/open-webui/security/advisories/GHSA-3xpf-xq7r-v8c5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 8.2 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
OSV 3.1 8.2 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi open-webui
>=0.9.0, <0.11.0
0.11.0

Affected products

  • open-webui open-webui

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-1021 Improper Restriction of Rendered UI Layers or Frames

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.