What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-15 · updated 2026-06-17
• Weakness: CWE-79

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 products

• open-webui: before 0.9.3 — fixed in 0.9.3

How to fix

Upgrade to a fixed version: open-webui 0.9.3. Check the vendor advisory for mitigations.

References

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

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