Medium severity · published May 15, 2026
CVE-2026-45318
Open WebUI: Stored XSS via unsanitized Office/Excel/DOCX file preview rendering ({@html} without DOMPurify)
5.4
CVSS
0.2%
EPSS
No
On KEV
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
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
open-webui · open-webui
< 0.9.3 · source: vendor
OW
Open Webui · Openwebui
before 0.9.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45318
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45318
Exploit
https://github.com/open-webui/open-webui/security/advisories/GHSA-hcwp-82g6-8wxc
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