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CVE-2026-45318

Open WebUI: Stored XSS via unsanitized Office/Excel/DOCX file preview rendering ({@html} without DOMPurify)

Published: May 15, 2026Updated: May 18, 2026 Sources: CVE List NVD BDUCWE-79
NVD MITRE
5.4CVSSMEDIUM
EPSS Score
0.2%
Top 89.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.3, his advisory tracks a regression of the original Excel-preview XSS (CVE-2026-44549). The same root cause — XLSX.utils.sheet_to_html() output rendered via {@html excelHtml} without DOMPurify — was reintroduced sometime after v0.8.0 and is exploitable again This vulnerability is fixed in 0.9.3.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:RS:CC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

open-webuiopen-webui
On-premWeb App
AI / ML / ai-agent-tooling
open webuiopenwebui
On-premWeb App
AI / ML / ai-agent-tooling
Open WebUIСообщество свободного программного обеспечения
On-prem
Operating Systems / linux-distro
open-webuioss-projectAI / MLaka open-webui/open-webui, open-webui
openwebuioss-projectAI / MLaka open webui
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://github.com/open-webui/open-webui/security/advisories/GHSA-hcwp-82g6-8wxc
github.com

Timeline

Published
May 15, 2026
Last Updated
May 18, 2026

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