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Fencer Vulns
high 8.1

CVE-2026-45665 json

Open WebUI: Stored XSS in Banner Component via Improper Sanitization Order

published 2026-05-14 5 mo ago modified 2026-06-17 4 mo ago also GHSA-cqp4-qqvg-3787 , EUVD-2026-30664

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 26%
public exploits
0
none known

Summary

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.8.0, a Stored Cross-Site Scripting (XSS) vulnerability exists in the Banner component due to an improper sanitization order (specifically, DOMPurify is executed before the marked library). This vulnerability allows a compromised or malicious administrator to plant a malicious payload in the global banner. Crucially, this vector enables Privilege Escalation, as the malicious banner is rendered for all users, including the Super Admin (Primary Admin). Consequently, the payload successfully bypasses the existing security mechanism. An attacker can leverage this to steal the Super Admin's session token This vulnerability is fixed in 0.8.0.

Patch / fix

  • npm open-webui 0.8.0
  • openwebui open_webui 0.8.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
5 mo ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/open-webui/open-webui/security/advisories/GHSA-cqp4-qqvg-3787 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm open-webui
<0.8.0
0.8.0

Affected products

  • open-webui open-webui

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

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.