Vulnerability · Published May 15, 2026 · Assigned by GitHub_M

CVE-2026-45318Open WebUI: Stored XSS via unsanitized Office/Excel/DOCX file preview rendering ({@html} without DOMPurify)

Medium 5.4

In plain English

A medium-severity cross-site scripting in open-webui from open-webui. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.2%top 88.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	open-webui	0.9.3	GHSA-hcwp-82g6-8wxc
PyPI	open-webui	0.9.3	PYSEC-2026-2731

Affected products (as reported)

Vendor	Product	Versions
open-webui	open-webui	< 0.9.3

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

References

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